Marked fluoropolymer surfaces and method of manufacturing same

ABSTRACT

A method of manufacturing a coated low-friction medical device, such as low-friction medical tubing, including applying a coating to one or more selected portions of a surface of low-friction medical tubing to indicate at least one marking formed along the surface of the low-friction medical tubing, and simultaneously or substantially simultaneously: (a) curing the applied coating to a designated temperature (which is above the temperature at which the low-friction medical tubing begins to decompose and shrink) to adhere the applied coating to the surface of the low-friction medical tubing, (b) utilizing one or more anti-shrinking devices to counteract or otherwise inhibit the shrinking of the low-friction medical tubing, and (c) exhausting any harmful byproducts resulting from curing the low-friction medical tubing to a temperate above the temperature at which the low-friction medical tubing begins to decompose.

PRIORITY CLAIM

This application is a continuation of, claims priority to and thebenefit of U.S. patent application Ser. No. 15/654,117, filed on Jul.19, 2017, which is a continuation of, claims priority to and the benefitof U.S. patent application Ser. No. 14/526,099, filed on Oct. 28, 2014,now U.S. Pat. No. 9,744,271, which issued on Aug. 29, 2017, which is acontinuation of, claims priority to and the benefit of U.S. patentapplication Ser. No. 13/416,743, filed on Mar. 9, 2012, now U.S. Pat.No. 8,900,652, which issued on Dec. 2, 2014, which claims priority toand the benefit of U.S. Provisional Patent Application No. 61/452,380,filed on Mar. 14, 2011, the entire contents of which are eachincorporated by reference herein.

BACKGROUND

Medical tubing or tubes are commonly inserted into humans or animals fortherapeutic and diagnostic medical procedures. Surgeons or other medicalprofessionals must often be able to determine the specific distance thatthe medical tubing is inserted into a body of a patient. The accurateplacement of the medical tubing is usually critical to the procedure. Ifmedical tubing is inserted too far into a patient, it could tear,puncture, or otherwise cause damage to internal bodily tissues, vessels,and/or organs, which could be harmful or potentially fatal to thepatient. Alternatively, if not inserted far enough, the procedure maynot be successfully performed. Accordingly, certain medical tubing ismarked with visual indicia of one or more colors at measured intervalsalong the length of the medical tubing to indicate to the user thelength, orientation, size, or diameter of the medical tubing insertedinto a patient. For example, to assist the surgeons or other medicalprofessionals, directional arrows and/or bands of various colors areoften marked on a surface of the medical tubing to enable the surgeon todenote orientation of the medical tubing.

One potential problem with such medical tubing is that the markingsplaced at measured intervals along the length of the medical tubing maybe inaccurate. That is, such markings may be slightly misplaced (i.e.,are not placed at the exact location along the length of the medicaltubing indicated to the medical professional). For example, a markingthat is supposed to indicate to a medical professional that a mark is2.00 inches (or 5.08 centimeters) from a distal end of the medicaltubing may be misplaced and actually be 2.10 inches (or 5.33centimeters) from the distal end of the medical tubing. In the medicalindustry and specifically in the field of medical tubing that isinserted into a patient's body, such inaccuracies may be harmful orpotentially fatal. In other words, when marked medical tubing isinserted into a body, such slight inaccuracies in the placement of theindicated marking may cause the medical tubing to be inserted too farinto a patient (which is associated with the above-described risks tothe patient) or not far enough into a patient (which is associated withthe above-described risks to the patient). Accordingly, accurateplacement of markings along the length of medical tubing is criticalwhen such medical tubing is inserted into a patient.

Additionally, certain known medical tubing can “stick” to tissues,catheters, or other surfaces during insertion or extraction. If medicaltubing sticks to other surfaces as it is inserted into a body, thesurgeon or other medical professional must apply a greater insertionforce to the medical tubing to reinitiate movement. Once movement isreinitiated, the opposing force immediately decreases so that themedical tubing is caused to quickly accelerate into or out of the body.Such extreme movements increase the risk of scraping, rubbing, tearing,puncturing, or otherwise damaging a patient's internal tissues due tomisplacing the end of the medical tubing in the patient.

To address such issues, certain know medical tubing has been formed fromone or more low-friction, low surface energy materials, such aspolytetrafluoroethylene (PTFE). This medical tubing, such as solid PTFEtubing, non-solid PTFE tubing, cellular PTFE tubing, porous PTFE tubing,and expanded PTFE tubing (known commonly as e-PTFE), reduces the amountof friction between the medical tubing and bodily tissues, catheters, orother surfaces. Accordingly, such low-friction medical tubing is lesslikely to stick to other surfaces and therefore gives surgeons or othermedical professionals more control over the insertion speed and depth,which reduces the risk of harm to the patient by reducing theabove-described “slip-stick” phenomena. Such low-friction medical tubinggenerally has a smooth very slippery outer surface that will not scrape,irritate, or snag tissues, vessels or arteries. However, because of theextremely low surface energy of the smooth, very slippery low-frictionsurfaces of such medical tubing, there are very limited methods forsecurely placing and permanently adhering markings on such low-frictionmedical tubing, such as PTFE tubing.

One known method of marking low-friction medical tubing and specificallyPTFE tubing, is to print or otherwise deposit ink (or paint) on thesurface of the low-friction medical tubing and then cure the depositedink at a cure temperature that does not affect or otherwise degrade thePTFE tubing. For example, for tetrafluoroethylene-hexafluoropropylene(FEP) Striping Ink manufactured by Colorant Chromatics, ColorantChromatics recommends applying the FEP Striping Ink on a PTFE substrateand curing the applied FEP Striping Ink at 509° F. (265° C.). In anotherexample, for GEM® WB1150 High-Temp Striping Ink manufactured by GEM®,GEM® recommends applying the High-Temp Striping Ink to a PTFE substrateand curing the applied High-Temp Striping Ink at 509° F. (265° C.). Inanother example, for GEM® WB1140 High-Temp Marking Ink manufactured byGEM®, GEM® recommends applying the High-Temp Marking Ink to a PTFEsubstrate and curing the applied High-Temp Marking Ink at 509° F. (265°C.).

It should be appreciated that the cure temperature of each of these inksis at or below 550° F. (288° C.) because while PTFE has a meltingtemperature of 621° F. (327° C.), PTFE begins to decompose or break downas the PTFE is heated to temperatures above 500° F. (260° C.). Suchdecomposition of the PTFE can generate toxic or noxious gasses and otherharmful airborne particles. Specifically, DuPont™ (i.e., a manufacturerof PTFE) expressly warns that PTFE should not exceed 500° F. (260° C.)and that fumes released by PTFE heated above 500° F. (260° C.) canproduce symptoms referred to as “polymer fume fever”. Accordingly, toavoid the PTFE decomposing and emitting harmful byproducts, knownmethods of marking PTFE tubing with inks (or paints) expressly requirethat the inks or paints be cured at a temperature below the temperaturewhich PTFE begins to decompose and possibly emit harmful byproducts.

It should be further appreciated that when PTFE tubing is heated totemperatures above 500° F. (260° C.), not only can the PTFE begin todecompose, but the dimensions of the PTFE tubing can begin to change.That is, the PTFE tubing can warp, distort, contract or otherwise shrinkdue to such temperatures. This warping of the PTFE tubing may result inthe uncured or wet ink (or paint) markings previously placed at correctmeasured intervals along the length of the PTFE tubing prior to curingto become inaccurate and misplaced (i.e., not placed at the exactlocation along the length of the PTFE tubing indicated to the medicalprofessional). As described above, for medical tubing that is insertedinto a patient's body, such inaccuracies may be harmful or potentiallyfatal. Accordingly, to avoid these undesired dimensional changes (andpotential accompanying inaccuracies in the placement of markings) toPTFE tubing that occur when PTFE tubing is heated to temperatures above500° F. (260° C.), known methods of marking PTFE tubing with inks (orpaints) heat the PTFE tubing below the temperature which PTFE tubingbegins to warp or otherwise shrink.

In light of the known problems with heating PTFE to temperatures at orabove the temperature which PTFE begins to decompose and warp, knownmethods of marking PTFE tubing is to print ink or otherwise deposit inkon the surface of the PTFE tubing and then cure the deposited ink to atemperature below the temperature which PTFE begins to decompose andwarp. However, one known problem with marking this low-friction medicaltubing is that the marked medical tubing (formed from PTFE which is alow-friction, low-surface energy, relatively inert and very slipperymaterial) resists bonding with such inks (or paints). That is, becausethe bond strength of the ink to the low surface energy PTFE surface isvery weak, the slippery surface of this low-friction medical tubingoften allows inks printed on this type of medical tubing to easily peelor flake off the tubing (e.g., the ink can generally be scratched offwith a human fingernail rubbing the deposited ink). If the ink (orpaint) peels or flakes off or dislodges inside a patient's body, suchink (or paint) may harm the patient (as the ink is not as inert as thePTFE tubing). Ink may also rub or peel off before or during use of themedical tubing, thus destroying the usefulness of the markings, andincreasing the risk that the medical tubing will be inserted either toodeep, or not deep enough (and harm the patient and/or render the medicalprocedure ineffective).

Furthermore, many types of commercially available medical tubing have arelatively small outer diameter such that even thin layers of ink cansignificantly increase the measurable total outer diameter of themedical tubing. By significantly increasing the outer diameter ofcertain marked portions of the medical tubing and not increasing theouter diameter of certain other unmarked portions of the medical tubing,grooves or valleys can be created in the outer surface of thelow-friction medical tubing. The shoulders of these bumps or protrusionscan have relatively sharp edges which can scrape or irritate bodilytissues, snag vessels or arteries of the patient, or otherwise causedamage and/or trauma to the patient. When inserting medical tubing intodelicate areas, such as various organs, the brain and/or the heart,damage caused by even the smallest of such bumps or protrusions can beharmful and potentially fatal for the patient. Additionally, creatingdifferent outer diameters along the length of the medical tubing tendsto increase the required insertion force and decreases the control asurgeon or other medical professional can exercise over the speed anddepth of an insertion. Therefore, such known methods of markinglow-friction medical tubing adversely affects the function of thelow-friction medical tubing.

Accordingly, a need exists for improved markings on low-friction medicaldevices, and specifically medical devices made from PTFE and blends ofPTFE polymers. More specifically, a need exists for improved markings onsolid PTFE medical tubing, non-solid PTFE medical tubing, expanded PTFEmedical tubing (known commonly as e-PTFE), porous PTFE medical tubing,and/or cellular PTFE medical tubing. Such a need exists for suchlow-friction medical tubing with markings that are permanently bonded tothe surface of the low-friction medical tubing, that are indelible(i.e., not readily or easily removable by solvents or liquids andrelatively abrasion resistant), that are accurately placed on thelow-friction medical tubing, that do not significantly increase ordecrease the diameter of the low-friction medical tubing (i.e., do notsignificantly protrude from the surface) and that do not significantlyadversely affect the function of the low-friction requirements ofmedical tubing.

SUMMARY

The present disclosure relates in general to low-friction, low surfaceenergy and/or non-stick medical devices, and specifically tolow-friction, low surface energy and/or non-stick medical tubing havingvisible markings, and a method for manufacturing the same. Morespecifically, the present disclosure relates to applying a coating toone or more selected portions of a surface of low-friction medicaltubing, and simultaneously or substantially simultaneously: (a) curingthe applied coating to a designated temperature (which is above thetemperature at which the low-friction medical tubing begins to decomposeand shrink) to adhere the applied coating to the surface of thelow-friction medical tubing, (b) utilizing one or more anti-shrinkingdevices to counteract or otherwise inhibit the shrinking of thelow-friction medical tubing, and (c) exhausting any harmful byproductsresulting from curing the low-friction medical tubing to a temperateabove the temperature at which the low-friction medical tubing begins todecompose.

The low-friction medical tubing can be a cylindrical body made from anysuitable fluoropolymer, such as any suitable polytetrafluoroethylene(PTFE) including, but not limited to: a solid PTFE, a non-solid PTFE, aporous PTFE, a cellular PTFE or an expanded PTFE (known commonly ase-PTFE), and at least one coating selectively applied to one or morespaced apart selected portions of the outer surface of the body. Thebody of the medical tubing is generally elongated, has a proximal end, adistal end, an outer surface, and an inner surface which defines onelumen (or a plurality of distinct lumens). The coating includes a binderor bonding material which, when cured at a designated temperature abovethe decomposition or melting temperature of PTFE, causes the coating tomolecularly bond or otherwise adhere to portions or molecules of theouter surface of the low-friction and low-surface energy medical tubing.The coating also includes one or more pigments of a color or hue thatcontrasts the color of the outer surface of the cylindrical body. Such aconfiguration facilitates that when the coating is selectively appliedto different portions along the length of the low-friction cylindricalbody, the medical tubing includes markings which enable a surgeon orother medical professional to determine the length of the medical tubinginserted into a body of a patient by observing the markings on theportion of the medical tubing located exterior to the body of thepatient.

In one embodiment, a coating is applied to selected portions the surfaceof the cylindrical body of the low-friction medical tubing, such as PTFEtubing. In one embodiment, to apply the coating to selected portion ofthe body, the low-friction body is placed in, attached to or otherwisecoupled with a shielding device. The shielding device protects, shieldsor mask the parts of the outer surface of the body which are not desiredto be coated or marked. In one embodiment, the shielding device includesone or more masking members spaced apart along the length of theshielding device. In this embodiment, the spacing of the gaps betweenmasking members corresponds to the markings to be indicated along thelength of the cylindrical body of the low-friction medical tubing. Itshould be appreciated that the shielding device may be configured tocorrespond with any suitable combination of lengths and patterns toindicate different lengths and locations on the body of the medicaltubing.

Once placed in the shielding device, a coating is applied to one or moreunprotected, unshielded or unmasked portions of the surface of the bodyof the low-friction medical tubing (i.e., the coating is applied toselected portions of the surface of the body of the medical tubing). Thecoating includes a binder such as an epoxy, phenolic, phenoxy,polyimide, polyamide, polyamide-amide, polyphenylene sulfide,polyarylsulfone, polyethylene, polytetrafluoroethylene, fluorinatedethylene propylene, perfluoroalkoxy,tetrafluoroethylene-hexafluoropropylene (FEP), polyetheretherketone(PEEK), polyetherketone (PEK), tetrafluoroethylene perfluoromethyl vinylether copolymer (MFA), or any other suitable binder or resin. Thecoating also includes at least one pigment or a combination of differentpigments, such as any suitable organic pigment, inorganic pigment,extender pigment, magnetic receptive pigment and/or laser excitablepigments.

In one embodiment, a plurality of different coatings are respectivelyapplied to a plurality of different unprotected, unshielded or unmaskedportions of the surface of the body of the low-friction medical tubing.In this embodiment, the different coatings each include differentcolored pigments such that after the coatings are applied to differentportions of the surface of the body of the low-friction medical tubing,the low-friction medical tubing includes different colored markings.

In other embodiments, depending on the shape of the medical tubing andthe configuration of the shielding device, the coating is applied in twoor more different or separate steps. For example, because of thecylindrical shape of the body of the medical tubing, the coating isapplied to one side of the body of the medical tubing via a plurality ofcoating applications, then the shielding device (including the attachedbody of the medical tubing) is rotated and the coating is applied toanother side of the body of the medical tubing via another plurality ofcoating applications.

After applying the coating(s) to the desired portion of the body of thelow-friction medical tubing, and drying or semi-curing the appliedcoating (so the coating is sufficiently dry and physically stable), thecoated body of the medical tubing is removed from or decoupled from theshielding device. At this point, the coated body of the medical tubingincludes one or more marked codes or patterns which denote distance fromthe distal end of the body of the medical tubing, the proximal end ofthe body of the medical tubing, the centerline of the body of themedical tubing or any suitable point or location of the body of themedical tubing required by the medical tubing manufacturer or themedical tubing designer.

After drying or semi-curing the applied coating, as further explainedbelow, the coated medical tubing is placed in, attached to or otherwisecoupled with one or more anti-shrinking devices. In one such embodiment,the anti-shrinking device holds the distal and proximal ends of the bodyof the coated medical tubing stationary or in place (such as by holdingeach end with a suitable holder or clamp). In another such embodiment,the anti-shrinking device additionally or alternatively includes one ormore support members, including solid and/or liquid support members,which are inserted into the lumen(s) of the PTFE tubing. In oneembodiment, after securing the coated medical tubing, the body of thecoated medical tubing is suitably further or finally cured at adesignated temperature, such as 650° F. (343.33° C.) for a designatedperiod of time, such as fifteen minutes. It should be appreciated thatthe further cure temperature is above the manufacturer's recommended andstated maximum temperature of 500° F. (260° C.) at which PTFE begins todecompose, soften, weaken, distort or otherwise warp. Such a curetemperature provides increased adhesion of the coating to the surface ofthe PTFE tubing (compared to curing coatings at a temperature at orbelow the 500° F. (260° C.) at which PTFE begins to decompose and warp).More specifically, by curing the coated PTFE tubing to a designatedtemperature, such as 650° F. (343.33° C.), both the binder of thecoating and the molecules of the PTFE at or near the outer surface ofthe body of the PTFE tubing melt or begin to fuse together in either amelt flow adhesion process or a sintering process depending on thecomposition and formulation of the PTFE tubing, and the composition andformulation of the applied pigmented coating. In this embodiment, themelted coating and the melted molecules of the PTFE bond or otherwiseadhere to each other to adhere the coating, and specifically thepigments in the coating, to the surface of the body of the PTFE tubing.Accordingly, by curing the PTFE tubing to a temperature above which thePTFE tubing begins to degrade, an increased adhesion of the coating tothe surface of the PTFE tubing is achieved (and thus a reduction in thepeeling off or dislodging of the coating on the surface of the PTFEtubing is also achieved).

It should be further appreciated that because one or more portions ofthe PTFE tubing disclosed herein are heated to a temperature above thedecomposition temperature of PTFE, the present disclosure provides thecure of the applied coatings in a controlled environment with theappropriate effluent filtration systems, such as appropriate carbonfiltration systems, which absorbs harmful byproducts of thedecomposition of the PTFE and thus minimizes any exposure to harmfulbyproducts emitted during the cure of the PTFE tubing. Additionally,because the PTFE only begins to decompose and warp at temperatures above500° F. (260° C.) and the decomposition of the PTFE is a gradualprocess, the amount of time the further cure occurs is limited to thedesignated period of time to facilitate that only the molecules of thePTFE at or near the outer surface of the body of the PTFE tubing beginto melt and the applied coating adheres to the outer surface of the bodyof the PTFE tubing. Such limits to the amount of time the PTFE is abovethe recommended maximum use temperature of 500° F. (260° C.)accomplishes that the amount of decomposition and emission of anyharmful byproducts, if any, of the PTFE is minimal.

As described above, when PTFE tubing is cured to temperatures above therecommended maximum use temperature of 500° F. (260° C.), the dimensionsof the PTFE tubing begin to change. Accordingly, to counteract anyshrinking that might occur when the PTFE tubing is further cured at adesignated temperature, such as at least 650° F. (343.33° C.) for adesignated period of time, one or more anti-shrinking devices areutilized to secure PTFE tubing and inhibit, reduce or prevent suchshrinking along the length of the body of the PTFE tubing. That is, asdescribed above, compared to known methods of marking PTFE tubing, ahigher cure temperature facilities a stronger bond or adhesion of thecoating to the surface of the PTFE tubing, but the higher curetemperature is accompanied by potential warping of the PTFE tubing.Thus, the present disclosure employs the higher cure temperature whilesimultaneously accounting for or otherwise counteracting, limiting orpreventing this potential shrinking of the length (and/or diameter) ofthe PTFE tubing.

More specifically, for certain low-friction medical tubing, such as theexample PTFE tubing described herein, because: (i) the body of the PTFEtubing contracts or shrinks when the PTFE tubing is cured or heated to atemperature, such as at least 650° F. (343.33° C.), (ii) the shieldingdevice includes gaps between the masking members (which are spaced apartat measured intervals along the length of the shielding device), and(iii) these gaps correspond with the exact locations of the intendedmarkings to be placed at measured intervals along the length of the bodyof the PTFE tubing, to ensure that the markings on the fully cured PTFEtubing correspond with the locations of the intended markings on thefinished PTFE tubing, one or more anti-shrinking devices are employed.In one such embodiment, the anti-shrinking device includes one or moreclamps or holders which secure or otherwise hold stationary the ends ofthe body of the PTFE tubing during the further cure. In another suchembodiment, the anti-shrinking device includes a support member which isinserted into the lumen (or into one or more of the plurality of lumens)of the PTFE tubing to secure or otherwise hold the body of the PTFEtubing stationary during the further cure. In different suchembodiments, this supporting procedure includes a liquid anti-shrinkingdevice, a gas anti-shrinking device and/or a solid anti-shrinkingdevice. In different such embodiments, this supporting procedureincludes a two-dimensional anti-shrinking device and/or athree-dimensional anti-shrinking device. In these embodiments, suchsecuring of body of the PTFE tubing thus prevents, limits or reduces thecontracting or shrinkage of the length of the body of the PTFE tubingwhen heated to a temperature such as at least 650° F. (343.33° C.) andalso accomplishes that, after the further or final cure, the actualmarkings along the length of the body of the PTFE tubing will stillaccurately correspond to the intended markings placed at measuredintervals along the length of the body of the PTFE tubing. Providingsuch accurate markings along the length of the body of the PTFE tubingenables the surgeon or other medical professional to insert the markedPTFE tubing into a patient at the proper position or depth andfacilitates a verification to the surgeon or other medical professionalthat the marked PTFE tubing is inserted into the patient at the properposition or depth. Such accurate placement of the markings benefitspatients by reducing the chance that a medical professional will rely oninaccurate markings when inserting the PTFE tubing into the patient (andpotentially reduce the chance that the patient will be harmed by anyreliance on inaccurately placed markings).

After the further or final cure, the resulting coated low-frictionmedical tubing includes areas of contrasting color along the length ofthe medical tubing which results in specific length markings at measuredintervals. The markings of such width, depth or distance of theresulting medical tubing enables surgeons or other medical professionalsto determine, based on a predetermined pattern known to the device user,the length or depth of the medical tubing inserted into a patient,whether from the proximal or distal end. It should be appreciated thatthe markings disclosed herein are not limited to indicating lengths, butalso can indicate one or more of: a size of the medical tubing, a typeof the medical tubing, a material of the medical tubing, a part numberof the medical tubing, a serial number of the medical tubing, a lotnumber of the medical tubing, a manufacturing date of the medicaltubing, a manufacturer of the medical tubing, at least one property orinstruction associated with the medical tubing, at least one warning, atleast one directional arrow, at least one location arrow, at least onebar code or other code, at least one band or stripe along the entirelength or along selected lengths from the distal end to the proximal endof the medical tubing, a stripe applied to the outer diameter either ina longitudinal manner or a spiral manner around and along a specified orthe entire length of the diameter of the medical tubing, at least onelinear line, at least one band or stripe along the longitudinal axis ofthe medical tubing, at least one spiral patterned line, band or stripealong the length of the medical tubing, a plurality of parallel lines,bands or stripes, a plurality of perpendicular lines, bands or stripes,a plurality of transverse lines, bands or stripes, or any combinationthereof.

In one embodiment, the coated portions of the body of the low-frictionmedical tubing are exposed to temperatures higher than the temperaturesthat will deform the low-friction tubing (i.e., 500° F. (260° C.)) andthe uncoated portions of the body of the low-friction medical tubing arenot subjected to such high temperatures. Such selective curing ofcertain portions of the body of the low-friction medical tubing (i.e.,the coated portions) and selectively not curing certain other portionsof the body of the low-friction medical tubing (i.e., the uncoatedportions) causes the binder of the coating to bond or otherwise bindwith the surface of the body of the low-friction medical tubing and thecoated portions of the body of the medical tubing to be a differentcolor than the color of the uncoated, uncured portions of the body ofthe medical tubing. It should be appreciated that such selectivelyheating of certain portions of the PTFE tubing prevents thedecomposition along the entire length of the body of the PTFE tubing andrather provides for the selective decomposition of certain portionsalong the length of the PTFE tubing.

In one embodiment, in addition to compensating or accounting for anydimensional changes (i.e., any shrinking or contracting) along thelength of the body of the low-friction medical device, such as the PTFEtubing, any dimensional changes occurring to the diameter of the body ofthe low-friction medical device are also compensated or accounted for.Specifically, in this embodiment, since heating or curing of the PTFE toa temperature of at least 650° F. (343.33° C.) causes the body of thePTFE tubing to contract or shrink, curing the coated portions of thebody of the PTFE tubing (while not heating or limiting heat to theuncoated portions of the body of the PTFE tubing) causes the diameter ofthe body of the PTFE tubing at these coated, cured portions to contractor shrink. In one such embodiment, the thickness or amount of thecoating applied to these portions of the PTFE tubing is configured tocompensate for the reduction in the diameter at these coated, curedportions of the PTFE tubing. Such application of an amount of coatingwhich equals or substantially equals the amount the outer diameter ofthe body of the PTFE tubing is reduced facilitates that the uncoatedportions of the resulting PTFE tubing will have the same orsubstantially the same outer diameter as the coated portions of theresulting PTFE tubing. Such equal outer diameters reduces or preventsgrooves or valleys or bumps or protrusions from being created in thesurface of the marked PTFE tubing. That is, by accounting for thesubsequent reduction in the outer diameter of the PTFE tubing whendetermining an amount of coating to apply to certain portions of thePTFE tubing, less bumps or protrusions having shoulders with sharp edges(which can scrape or irritate bodily tissues, snag vessels or arteriesof the patient, or otherwise cause damage and/or trauma to the patient)are created in marking the PTFE tubing disclosed herein.

It should be appreciated that while the low-friction medical devicedisclosed herein is often referred to and illustrated as medical tubingor PTFE tubing, the present disclosure of applying a coating to one ormore selected portions of a surface of low-friction medical device, andsimultaneously or substantially simultaneously: (a) curing the appliedcoating to a designated temperature (which is above the temperature atwhich the low-friction medical device begins to decompose and shrink) toadhere the applied coating to the surface of the low-friction medicaldevice, (b) utilizing one or more anti-shrinking devices to counteractor otherwise inhibit the shrinking of the low-friction medical device,and (c) exhausting any harmful byproducts resulting from curing thelow-friction medical device to a temperate above the temperature atwhich the low-friction medical device begins to decompose; may beemployed with any suitable low-friction device that is inserted into apatient or connects to a low-friction device that inserts a device intoa patient in connection with any medical procedure and/or any suitablelow-friction device that is employed or utilized outside of the medicalfield. Such suitable low-friction medical devices and such suitablelow-friction non-medical devices include, but are not limited to:medical tubes, medical wires, medical tapes, medical guide wires,catheters, needles, soft tissue needles, biopsy devices, biopsy tubularsampling devices, soft tissue biopsy devices, soft tissue tubulardevices, hook-type biopsy devices, laminates, vents, medical patches,cannulas, probes, electrosurgical electrodes, sheets, gaskets, blades,knives and any suitable low friction, low surface area medical devicewhich flexes, bends or is required to move in any suitable direction.Such suitable low-friction non-medical devices include, but are notlimited to: sight tubes, air meters, gas meters, flow meters, labware,containers, plates, sleeves, molded devices, vessels, and any suitablelow friction, low surface area non-medical device. Moreover, indifferent embodiments, the low-friction medical device and/orlow-friction non-medical device is constructed from any suitablelow-friction and/or low surface energy material, including but notlimited to: solid PTFE, non-solid PTFE, expanded PTFE, porous PTFE,micro-porous PTFE, cellular PTFE, fluorinated ethylene propylene (FEP),polyethylene (PE), perfluoroalkoxy (PFA) and/or any low surface energyparticulate material.

It is therefore an advantage of the low-friction medical device andmethod disclosed herein to provide a marked low-friction medical devicehaving markings which do not affect the function or form of thelow-friction medical device and which enable a surgeon or other medicalprofessional to determine the length of a medical device inserted into apatient's body, and to control the speed and consistency of the tactilefeel at which the medical device is being inserted or extracted from thepatient's body. Such medical device does not require special handlingthat may be required to prevent any non-adhered or non-bonded markingsfrom being dislodged during a medical procedure or during a cleaningprocedure. The medical device and method disclosed herein furtherprovides a marked medical device with a smooth, continuous low-frictionsurface with a substantially constant diameter which reduces occurrencesof or otherwise prevents the medical device from snagging, sticking,tearing, or otherwise damaging or irritating vessels, arteries, or othertissues of a patient during insertion, positioning, and extraction ofthe medical device. That is, the marked low-friction medical devicedisclosed herein assists a surgeon or other medical professional insmoothly, easily, accurately, and safely inserting and positioning themedical device in a patient's body during a medical procedure with amore consistent tactile “feel” (compared to a marked medical device withprotrusions due to the thickness of an added layer of pigmented marking)and know what amount of the medical device is inserted into thepatient's body and what amount of the medical device remains outside ofthe patient's body. In other words, the marked low-friction medicaldevice disclosed herein, such as the solid PTFE medical device, thenon-solid PTFE medical device, the expanded PTFE medical device, theporous PTFE medical device, and the cellular PTFE medical device,disclosed herein each include markings that are permanently bonded tothe surface of the low-friction medical device, are configured to flexor bend and remain adhered to (i.e., not become dislodged from) the PTFEmedical device when the PTFE medical device flexes or bends wheninserted into a patient, that are indelible (i.e., not readily or easilyremovable by solvents or liquids and relatively abrasion resistant),that are accurately placed on the low-friction medical device, that donot significantly increase or decrease the diameter of the low-frictionmedical device (i.e., do not significantly protrude from the surface)and that do not significantly adversely affect the function of thelow-friction medical device.

Additional features and advantages are described herein, and will beapparent from, the following Detailed Description and the Figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a flow chart generally illustrating one embodiment of thedisclosed method of marking PTFE tubing.

FIG. 2A is a fragmentary perspective view generally illustratinguncoated PTFE tubing.

FIG. 2B is an end view of the uncoated PTFE tubing of FIG. 2A.

FIG. 2C is a fragmentary perspective view of a plurality of the PTFEtubes of FIG. 2A being positioned in an example shielding device.

FIG. 2D is a fragmentary perspective view of the PTFE tubes of FIG. 2Cbeing coated from a first direction to selectively coat portions of thesurfaces of each of the PTFE tubes.

FIG. 2E is a fragmentary perspective view of the PTFE tubes of FIG. 2Dbeing coated from a second, different direction to selectively coatportions of the surfaces of each of the PTFE tubes.

FIG. 2F is a fragmentary perspective view of the PTFE tubes and theshielding device of FIG. 2E being rotated.

FIG. 2G is a fragmentary perspective view of the PTFE tubes of FIG. 2Fbeing coated from the first direction to selectively coat portions ofthe surfaces of each of the PTFE tubes.

FIG. 2H is a fragmentary perspective view of the PTFE tubes of FIG. 2Gbeing coated from the second, different direction to selectively coatportions of the surfaces of each of the PTFE tubes.

FIG. 2I is a fragmentary perspective view of one of the coated,partially cured PTFE tubes of FIG. 2H removed from the example shieldingdevice.

FIG. 2J is a fragmentary perspective view of the coated, partially curedPTFE tubing of FIG. 2I being secured at each end by anti-shrinkingdevices.

FIG. 2K is a fragmentary perspective view of the coated PTFE tubing ofFIG. 2J being selectively cured while each end is secured.

FIG. 2L is a fragmentary side view of the cured, coated PTFE tubing ofFIG. 2K.

FIG. 3A is a fragmentary cross-sectional view of the coated, uncuredPTFE tubing.

FIG. 3B is a fragmentary cross-sectional view of the coated, partiallycured PTFE tubing of FIG. 3A

FIG. 3C is a fragmentary cross-sectional view of the coated, fully curedPTFE tubing of FIG. 3B.

FIG. 4A is a fragmentary perspective view comparing the length of theuncoated, uncured PTFE tubing to the length of the coated, cured PTFEtubing.

FIG. 4B are cross-sectional views, taken substantially along line IVB ofFIG. 4A, comparing the diameter of the uncoated, uncured PTFE tubing ofFIG. 4A to the diameter of the coated, cured PTFE tubing of FIG. 4A.

FIG. 5A is a fragmentary side view of the uncoated, uncured PTFE tubingdisclosed herein.

FIG. 5B is a fragmentary side view of the coated, uncured PTFE tubing ofFIG. 5A.

FIG. 5C is a fragmentary side view of the coated, partially cured PTFEtubing of FIG. 5D.

FIG. 5D is a fragmentary side view of the coated, further cured PTFEtubing of FIG. 5C.

FIG. 6A is a fragmentary side view of an alternative embodimentgenerally illustrating coated PTFE tubing.

FIG. 6B is a fragmentary side view of the coated PTFE tubing of FIG. 6Abeing cured while each end is unsecured.

FIG. 6C is a fragmentary side view of the coated, cured and shrunk PTFEtubing of FIG. 6B.

FIG. 7A is a fragmentary perspective view of an alternative embodimentgenerally illustrating a magnetic induction coil for selectively heatingportions of coated PTFE tubing.

FIG. 7B is a cross-sectional view, taken substantially along line VIIBof FIG. 7A, illustrating the diameter of the coated, uncured PTFE tubingof FIG. 7A.

FIG. 8 is a fragmentary perspective view of an alternative embodiment ofone of the coated PTFE tubes disclosed herein being cured in a curingdevice.

FIG. 9A is a fragmentary top perspective view of another exampleshielding device utilized in association with coating one or more PTFEtubes.

FIG. 9B is a fragmentary bottom perspective view of the exampleshielding device of FIG. 9A.

FIG. 9C is a fragmentary top perspective view of the example shieldingdevice of FIG. 9A coupled with a PTFE tube.

FIG. 10A is a fragmentary perspective view of a PTFE tube beingpositioned in an example shielding device.

FIG. 10B is a fragmentary perspective view of the PTFE tube of FIG. 10Abeing rotated.

FIG. 10C is a fragmentary perspective view of the PTFE tube of FIG. 10Bbeing coated from a first direction to selectively coat a first portionof the surface of the PTFE tube.

FIG. 10D is a fragmentary perspective view of the PTFE tube of FIG. 10Dbeing coated from the first direction to selectively coat a secondportion of the surface of the PTFE tube.

FIG. 11A is a fragmentary side view of a rotating PTFE tubing disclosedherein which is uncoated and uncured.

FIG. 11B is a fragmentary side view of the rotating PTFE tubing of FIG.11A which is coated and uncured.

FIG. 11C is a fragmentary side view of the rotating PTFE tubing of FIG.11B which is coated and partially cured.

FIG. 11D is a fragmentary side view of the rotating PTFE tubing of FIG.11D which is coated and further cured.

DETAILED DESCRIPTION

Referring now to the example embodiments of the present disclosureillustrated in FIGS. 1 to 8, the medical tubing illustrated in FIGS. 2Aand 2B is seen before having any coating applied thereto. In thisillustrated embodiment, the low-friction medical tubing includes acylindrical body 200 made from a fluoropolymer, such aspolytetrafluoroethylene (PTFE) (which includes a solid PTFE, a non-solidPTFE, a cellular PTFE, a porous PTFE, or an expanded PTFE). The body 200of the medical tubing is generally elongated, has a proximal end 202, adistal end 204, an outer surface 206, and an inner surface which definesa lumen 208. Since the PTFE tubing is constructed from the low-frictionmaterial of PTFE, such tubing includes the properties of high lubricity,high temperature use, high chemical resistance, and biocompatibility.The outer surface 206 is very slippery and more particularly has a verylow friction measurement or coefficient of friction measured at 0.10.

In one embodiment, before applying a coating to the surface of the bodyof the PTFE tubing, the PTFE tubing is prepared for coating as indicatedin block 102 of FIG. 1. In one such embodiment, the body of the PTFEtubing is cleaned with a cleaner to remove impurities which are presenton the surface of the PTFE tubing. Impurities such as oils may impedebonding of a coating to the outer surface of the body of PTFE tubing,and also may cause damage to a patient if inserted into a patient's bodyduring a medical procedure. The cleaner, such as a solvent, acidsolution or alkaline, is suitably applied, such as manually applied,mechanically applied or ultrasonically applied to the PTFE tubing. Inanother such embodiment, thermal heat, such as heat from a flame, openflame, infrared heat or hot air, is selectively applied to the PTFEtubing to clean the PTFE tubing prior to applying the coating. It shouldbe appreciated that any suitable cleaning method or any suitablecombination of cleaning methods may be used to clean the PTFE tubingprior to applying the coating.

After cleaning the outer diameter of the body of the PTFE tubing, one ormore parts of the body of the PTFE tubing not desired to be coated areblocked or shielded as indicated in block 104 of FIG. 1. As describedbelow, such blocking, protecting, shielding or otherwise suitablymasking of one or more parts of the body of the PTFE tubing enables thatcertain parts or portions of the PTFE tubing are coated and certainother parts or portions of the body of the PTFE tubing are not coated(as further discussed and illustrated below).

In one embodiment, one or more PTFE tubes are placed in, attached to orotherwise coupled with a suitable shielding device. In one embodiment,as seen in FIG. 2C, to enable a plurality of PTFE tubes to besimultaneously coated, a plurality of PTFE tubes 200 a, 200 b and 200 care simultaneously positioned in the shielding device.

In the illustrated embodiment of FIG. 2C, to protect or mask one or moreparts of the PTFE tubing, a shielding device 300 is utilized. Shieldingdevice 300 includes one or more masking members 302 a, 302 b, 302 c, 302d, 302 e, 302 f, 302 g and 302 h. Each masking member includes ordefines a plurality of grooves 304 to receive a portion of a PTFE tube.Each masking member is attached to a hinge 306 which enables rotation ofthe masking members. Such rotation enables masking members 302 a and 302e, masking members 302 b and 302 d, masking members 302 c and 302 g, andmasking members 302 d and 302 h to each be moved toward each other toengage the PTFE tubing in a closed position (as seen in FIG. 2D) andaway from each other to disengage the PTFE tubing in an open position(as seen in FIG. 2C). This example shielding device includes one or morelocking devices 308, such as fasteners connected to certain of themasking members, to lock the shielding device in the closed position. Itshould be appreciated that other suitable shielding devices may beemployed in accordance with the present disclosure.

In this illustrated embodiment, the gap or distance between the maskingmembers corresponds to the gap or distance that will be between themarkings on the marked PTFE tubing. It should be appreciated that thedistances between the masking members of the shielding devicecorresponds to different portions along the length of the body of thePTFE tubes. Accordingly, this embodiment facilitates that the portionsof the body of the PTFE tubes that correspond to the placement of themasking members of the shielding device are protected or masked (and theportion of the body of the PTFE tubes that do not correspond to theplacement of the masking members of the shielding device are notprotected or masked).

In one embodiment, to create equally spaced apart markings along thelength of the body of the PTFE tubing, the masking members of theshielding device are equally spaced apart. In another embodiment, tocreate unequally spaced apart markings along the length of the body ofthe PTFE tubing, the masking members of the shielding device areunequally spaced apart. Accordingly, it should be appreciated that bypositioning the masking members of the shielding device in any suitableconfiguration, markings in any desired pattern or any combination ofpatterns can be created on the surface of the body of the PTFE tubing.

In another embodiment, the shielding device includes one or more slots,openings or apertures that are designated lengths apart. For example, asseen in FIGS. 9A and 9B, to protect or mask one or more parts of thePTFE tubing, shielding device 320 is utilized. Shielding device 320includes a body 322 which includes or defines a channel 324 configuredto receive a portion of a PTFE tube. As also seen in FIGS. 9A and 9B,the body of shielding device includes a semi-cylindrical member or guardthat includes or defines one or more slots, openings or apertures 326.In this embodiment, the positioning of the slots of the shielding devicecorrespond to the positioning of the markings on the marked PTFE tubing.That is, the distances between the slots of the shielding devicecorresponds to the distances, along the length of the body of the PTFEtubing, between the markings on the PTFE tubing. Accordingly, thisembodiment causes portions of the body of the PTFE tubes that correspondto the slots of the shielding device to be not protected or masked (andthe portion of the body of the PTFE tubes that corresponds to theshielding device to be protected or masked).

After shielding one or more PTFE tubes using the shielding device, asindicated in block 106 of FIG. 1, a coating is applied along a portionor all of the unprotected or unmasked length of the surface of the bodyof each PTFE tube. In this embodiment, the application of the coating tocertain unblocked, unprotected, unshielded or otherwise unmasked partsor portions of the body of the PTFE tubing (coupled with the coating notbeing applied to certain blocked, protected, shielded or otherwisemasked parts or portions of the body of the PTFE tubing) accomplishesthat the coating is selectively applied to the surface of the body ofthe PTFE tubing.

In one embodiment, the coating includes a binder, such as an epoxy,phenolic, phenoxy, polyimide, polyamide, polyamide-amide, polyphenylenesulfide, polyarylsulfone, polyethylene, polytetrafluoroethylene,fluorinated ethylene propylene, perfluoroalkoxy,tetrafluoroethylene-hexafluoropropylene (FEP), polyetheretherketone(PEEK), polyetherketone (PEK), tetrafluoroethylene perfluoromethyl vinylether copolymer (MFA), an acid based PTFE, FEP or MFA primer, or anysuitable binder or resin. In one embodiment, the coating includes anultraviolet light cure resin to semi or fully cure the coating. Inanother embodiment, the coating includes an electron beam cure resin. Itshould be appreciated that the coating may include any suitable binderswhich, when cured, adheres to the surface of the PTFE tubing, and isflexible, stable, resistant to chemicals, and/or is readily sterilizedand resistant to contamination.

The coating also includes at least one pigment or combination ofpigments such as one or more suitable organic pigments, inorganicpigments, extender pigments, magnetic receptive pigments and/or laserexcitable pigments. The organic pigments (with low to moderate heatresistance and which are represented as bright colors) include, but arenot limited to: phthalocyanine blues and greens, diarylide yellows andoranges, quanacridone, naphthol and toluidine reds, carbizole violets,and carbon black. The inorganic pigments (with moderate to hightemperature resistance and which are represented as dull to moderatelybright colors) include, but are not limited to: iron oxide reds andyellows, chrome oxide greens, titanium oxide white, cadmium reds,ultramarine blues, moly oranges, lead chromate yellows, and mixed metaloxides of various shades of brown, yellow, blue, green and black. Theextender pigments (which are inorganic and provide areinforcing/strengthening function) include, but are not limited to:talc, calcium carbonate, silicate and sulfate, silica, mica, aluminumhydrate and silicate, barium sulfate (blanc fixe/barites), andattapulgite. The laser exciteable pigments (which are excited by laserenergy), such as near-infrared reflective pigements include, but are notlimited to: mica, pearl pigment, Kaolin and aluminum silicatederivatives, antomony trioxide, metallic pigment, aluminum flakepigment, iron oxide, and attapulgite. Additionally, the coating may alsoinclude one or more of the following functional pigments, such asconductive pigments, flattening pigments for controlling gloss, claysand other rheology modifying pigments. In another embodiment, thecoating includes one or more metal oxide pigments, and/or one or moreFDA non-objection status for food contact approved end use pigments.

In different embodiments, the coating is a Standard Technical AppliedResources, Inc. FEP Ink with the appropriate pigments, a StandardTechnical Applied Resources, Inc PTFE ink with the appropriate pigments,a GEM® WB1150 High-Temp Striping Ink with the appropriate pigments, aGEM® WB1140 High-Temp Marking Ink with the appropriate pigments, a GEM®7700 Band Marking coating with the appropriate pigments, a GEM® 6000Series High Temp Ink with the appropriate pigments, a GEM® 4700 SeriesPTFE Colorant coating with the appropriate pigments, a ColorantChromatics FEP Striping Ink with the appropriate pigments, a Tiger Inks& Coatings TIGERMARK T1000 Series coating with the appropriate pigments,a Xylan® 1514 low-friction coating with the appropriate pigments, aVICOTE® 700 Series coating with the appropriate pigments, a VICOTE® 800Series coating with the appropriate pigments, a DuPont™ 420 Seriescoating with the appropriate pigments, a DuPont™ 857N504 coating withthe appropriate pigments, a DuPont™ 851N504 coating with the appropriatepigments, a DuPont™ 857G504 coating with the appropriate pigments, aDuPont™ 851G504 coating with the appropriate pigments, a DuPont™ 851G204coating with the appropriate pigments, a DuPont™ 851G321 coating withthe appropriate pigments, a WHITFORD® OC 600 Series coating with theappropriate pigments, a WHITFORD® OC 600D8686Z coating, a WHITFORD® OC600D8686Z coating with the appropriate pigments, a WHITFORD® OC606D8881Z coating with the appropriate pigments, a WHITFORD® OC625D17012Z coating with the appropriate pigments, a WHITFORD® OC D10712Zcoating with the appropriate pigments, a WHITFORD® OC 625D8684Z coatingwith the appropriate pigments, a WHITFORD® OC 655D8692Z coating with theappropriate pigments, an MPC 992003 coating with the appropriatepigments, a Ultralon® OC Series coating with the appropriate pigments, aFluoroplate® 41141 Series coating with the appropriate pigmentsmanufactured by Orion Industries, or any suitable coating andspecifically any suitable coating which is manufactured withoutperfluorooctanoic acid (PFOA) material (as mandated by the EnvironmentalProtection Agency's requirement that PFOA materials be eliminated fromthe manufacturing process of certain coatings by 2015).

In the illustrated embodiment, the coating is applied by spraying theouter surface of the body of the PTFE tubing with the coating. Forexample, a layer approximately 0.0003″ to 0.0005″ thick of the wetcoating is applied to one or more unmasked portions of the outer surfaceof the body of the PTFE tubing. In this example, a wet coating is about25% solids (by volume) such that a coating which is 0.0005″ thick whenapplied wet will be 0.000125″ thick when the coating is fully cured. Inone such embodiment, as described below, the amount or thickness of thecoating applied to certain unblocked portions of the body of the PTFEtubing is determined based on the amount or thickness which the diameterof the PTFE tubing will contract or shrink when the PTFE tubing is fullycured.

In the illustrated embodiment, to account for the cylindrical shape ofthe body of the PTFE tubing, a coating is applied to one or more of theunshielded portions of the body of the PTFE tubing in a plurality ofsequential coating applications. For example, as seen in FIG. 2D, afirst coating 210 is applied to a first unshielded portion of the bodyof the PTFE tubing from a first direction. As seen in FIG. 2E, the firstcoating is then applied to the first unshielded portion of the body ofthe PTFE tubing from a second, different direction. In this illustratedembodiment, as seen in FIG. 2F, the shielding device (including the PTFEtubes) is rotated, such as the illustrated 180° rotation, to expose anuncoated surface of the first unshielded portion of the body of the PTFEtubing. Following this rotation, as seen in FIGS. 2G and 2H, tocompletely coat this portion of the body of the PTFE tubing, the coatingis then applied to the first unshielded portion of the body of the PTFEtubing from two different directions. In this illustrated embodiment,because of the shape of the body of the PTFE tubing, to completely coatthe unmasked portions of the body of the PTFE tubing, amulti-directional application process is implemented. In anotherembodiment, to account for the shape of the body of the PTFE tubing, thecoating is applied from one side of the shielding device at differentdirections and then the coating is applied from different directionsfrom the opposite side of the shielding device. In another embodiment,to account for the shape of the body of the PTFE tubing, the coating issimultaneously or substantially simultaneously applied from differentsides of the shielding device at different directions. Such processesensure that the coating is applied to the unblocked, unprotected,unshielded or otherwise unmasked portions of the body of the PTFEtubing.

In the illustrated embodiment, a plurality of different colored coatingsare applied to different unblocked, unprotected, unshielded or otherwiseunmasked portions of the body of the PTFE tubing. This embodimentfacilitates that different portions of the coated PTFE tubing will bedifferent colors to indicate different information to the medicalprofessional using the PTFE tubing. For example, as seen in FIG. 2I, afirst coating 210 a of a first color is applied to one or moreunblocked, unprotected, unshielded or otherwise unmasked portions of thebody of the PTFE tubing and a second, different coating 210 b of asecond, different color is subsequently applied to one or moreunblocked, unprotected, unshielded or otherwise unmasked portions of thebody of the PTFE tubing. In this example, the resulting coated PTFEtubing includes a first marking 212 a of a first color along one or moreportions of the PTFE tubing and a second marking 212 b of a second,different color along one or more different portions of the PTFE tubing.In another embodiment, at designated points on the body of the PTFEtubing, different colored coatings are applied and the marks are createdin a gradation of successively, incrementally darker colors to create aprogressively darker and darker mark to further enhance the ability tocreate distance codes or even directional force guides on the PTFEtubing.

After applying the coating, the coating is dried, semi-cured or slightlyunder-cured as indicated in block 108 of FIG. 1. In one exampleembodiment, the coated PTFE tubing is under cured to between 250° F.(121.11° C.) and 400° F. (204.44° C.). In another embodiment, the coatedPTFE is air dried for a designated period of time to enable the appliedcoating to dry. Such drying or partial curing of the coating causes thecoating to be sufficiently dry and physically stable.

After partially curing the coating, the PTFE tubing is removed from orotherwise decoupled from the shielding device as indicated in block 110of FIG. 1 and seen in FIG. 2I. As indicated in block 112 of FIG. 1, bothends of the coated PTFE tubing are then secured (i.e., held stationaryor otherwise held in place). In one such embodiment, as seen in FIG. 2J,a first or proximal end 202 of the body of the PTFE tubing is connectedto a first suitable holder or clamp 402 a of a securing device and asecond or distal end 204 of the body of the PTFE tubing is connected toa second suitable holder or clamp 402 b of the securing device. In oneembodiment, each clamp is configured to engage or secure a PTFE tubes.In another embodiment, each clamp is configured to engage or secure aplurality of PTFE tubes such that a plurality of PTFE tubes can besimultaneously secured (and thus cured simultaneously).

While the ends of the coated PTFE tubing remain secured to preventshrinking of the PTFE tubing, as indicated in block 114 of FIG. 1, thecoated PTFE tubing is suitably further or finally cured. In one suchembodiment, as seen in FIG. 2K, with the two clamps securing the ends ofthe PTFE tubing, the coated portions of the PTFE tubing is cured, suchas by radiated heat, to a designated temperature, such as 650° F.(343.33° C.) for a designated duration, such as fifteen minutes. In thisillustrated embodiment, radiated heat is directed to specific portionsof the coating by masking the uncoated portions of the PTFE tubing (witha suitable temperature resistant masking device configured to shield theuncoated portions of the PTFE tubing from the heat source). In anothersuch embodiment, the further or final curing process includes curing atthe coated portions of the PTFE tubing at a temperature between 610° F.(321.11° C.) to 1050° F. (565.56° C.). In this embodiment, the durationof the further or final cure depends on the further or final curetemperature, wherein a higher final cure temperature requires a shortercure duration and a lower final cure temperature requires a longer cureduration.

It should be appreciated that as described below, the further or finalcure is at such a designated temperature (i.e., above the recommendedmaximum temperature which exceeds the use temperature rating of PTFE andat which the PTFE tubing begins to warp) that the further cure causesthe body of the PTFE tubing to shrink or contract. Accordingly, thedisclosed embodiment of utilizing an anti-shrinking device, such as aplurality of clamps to secure the ends of the coated PTFE tubing for thefurther or final cure limits, inhibits or prevents the PTFE tubing fromshrinking or contracting along the length of the PTFE tubing.Specifically, the force applied by the clamps to the ends of the body ofthe PTFE tubing is of a force at least equal to the force of contractionof the PTFE tubing, thus limiting or preventing the length of the PTFEtubing from contracting. In certain embodiments, to provide the degreeof force necessary to limit or prevent the length of the PTFE tubingfrom contracting, for one or both ends of the PTFE tubing, a clamp isused which holds that end of the PTFE tubing tight enough to damage orcrush the end of the PTFE tubing. In these embodiments, after the PTFEis cured, the damaged ends of the PTFE tubing are cut off and discarded.It should be appreciated that in these embodiments, no coating isinitially applied to these discarded portions of the PTFE tubing and thecoatings are placed at designated intervals along the length of the PTFEtubing to account for the subsequent cutting off of these portions ofthe PTFE tubing.

The final cure causes the binder to melt and bond to the surface of thebody of the PTFE tubing. Specifically, in one embodiment, by curing thecoated PTFE tubing to a designated temperature of 650° F. (343.33° C.),both the binder of the coating and the molecules of the PTFE at or nearthe outer surface of the body of the PTFE tubing melt. The meltedcoating and the melted molecules of the PTFE bond or otherwise adhere toeach other to adhere the coating, and specifically the pigments in thecoating, to the surface of the body of the PTFE tubing. Morespecifically, because the PTFE is a thermoset and the binder material,such as FEP or MFA, is a thermoplastic, the final cure causes the meltflow PTFE at or near the outer surface of the body of the PTFE tubing tomelt and molecularly bond with the binder. Such a cure temperatureprovides increased adhesion of the coating to the surface of the body ofthe PTFE tubing (compared to curing coatings at the recommendedtemperature at or below the 500° F. (260° C.) at which PTFE begins todecompose and soften). Such bonding minimizes or ensures that thecoating will not easily or readily peel or rub off during use of thePTFE tubing and be left inside the patient's body. Moreover, suchbonding ensures that the coating will not readily rub or peel off beforeor after use of the PTFE tubing, thus destroying the usefulness of themarkings, and increasing the risk that the PTFE tubing will be insertedeither too deep, or not deep enough (and harm the patient and/or renderthe medical procedure ineffective). In other words, by curing the PTFEtubing to a temperature above which the PTFE tubing begins to degrade,an increased adhesion of the coating to the surface of the PTFE tubingis achieved (and thus a reduction in the peeling off or dislodging ofthe coating on the surface of the PTFE tubing is also achieved). Suchadhesion of the pigmented coating to the surface of the PTFE tubingprovides that when the PTFE tubing flexes or bends when inserted into apatient, the applied pigmented coating is enabled to also flex or bendand remain adhered to (i.e., not become dislodged from) the PTFE tubing.

It should be appreciated that different types of PTFE have differentmelting temperatures and thus the further or final cure temperature ofthe coated PTFE tubing is based, at least in part, on the constructionof the PTFE tubing. For example, a further or final cure temperature ofat least 650° F. (343.33° C.) is employed to cause the molecules ofsolid PTFE at or near the outer surface of the body of the solid PTFEtubing to melt. In another example, a further or final cure temperatureof at least 500° F. (260° C.) is employed to cause the molecules ofexpanded PTFE at or near the outer surface of the body of the expandedPTFE tubing to melt. Accordingly, by accounting for the meltingtemperature of the specific type of PTFE used to form the PTFE tubing(and further accounting for the same type of PTFE made from differentmanufacturers may have different melting temperatures), the presentdisclosure achieves an increased adhesion of the coating to the surfaceof each specific type of PTFE tubing while also minimizing the amount ofdecomposition and emission of any harmful byproducts caused by heatingsuch PTFE above the recommended maximum use temperature for thatspecific type of PTFE.

It should also be appreciated that because one or more portions of thePTFE tubing disclosed herein are heated to a temperature above theinitial decomposition temperature of PTFE, the cure of the appliedcoatings occurs in a controlled environment with the appropriate exhaustand filtration systems, such as appropriate carbon filtration systems,which absorbs harmful airborne effluent byproducts of the decompositionof the PTFE and thus minimizes any exposure to harmful byproductsemitted during the cure of the PTFE tubing. It should be furtherappreciated that because the PTFE only begins to decompose and soften attemperatures above 500° F. (260° C.) and the decomposition of the PTFEis a gradual process, the amount of time the further cure occurs islimited to the designated period of time to facilitate that only themolecules of the PTFE at or near the outer surface of the body of thePTFE tubing begin to melt and the applied coating adheres to the outersurface of the body of the PTFE tubing. Such limits to the amount oftime the PTFE is above the recommended maximum use temperature of 500°F. (260° C.) accomplishes that the amount of decomposition and emissionof any harmful byproducts, if any, of the PTFE is minimal. In thisembodiment, such limited duration of the further cure also facilitatesthat only the molecules of the PTFE at or near the outer surface of thebody of the PTFE tubing reach a temperature of at least 650° F. (343.33°C.) and other cured portions not at or near the outer surface of thebody of the PTFE tubing do not reach a temperature of at least 650° F.(343.33° C.).

For example, as illustrated in FIG. 3A, prior to the final cure, theapplied coating 212 and the outer surface 206 of the body of the PTFEtubing 200 are the same temperature or substantially the sametemperature (as indicated by the equally spaced apart thermaltemperature indicating hash markings). In this illustrated example, asseen in FIG. 3B and as indicated by the different spaced apart thermaltemperature indicating hash markings, near the beginning of the final orfurther cure, the heat is applied to the coated PTFE tubing such thatthe temperature of the coating 212 is increased to a second temperature(which is greater than the first temperature) and the molecules of thePTFE tubing at or near the outer surface 206 of the body of the PTFEtubing are increased to a third temperature (which is lower than thesecond temperature). As further seen in FIG. 3B, the heat is applied tothe coated PTFE tubing such that the molecules near the center of thePTFE tubing are increased to a fourth temperature (which is lower thanthe third temperature) and the molecules of the PTFE tubing at or nearthe lumen 208 of the PTFE tubing are increased to a fifth temperature(which is lower than the fourth temperature).

As seen in FIG. 3C, near the end of the final or further cure, thecoating 212 and the molecules of the PTFE tubing at or near the outersurface 206 of the body of the PTFE tubing are each increased to atemperature of at least 650° F. (343.33° C.) which causes both thebinder of the coating and the molecules of the PTFE at or near the outersurface of the body of the PTFE tubing to melt. The melted coating andthe melted molecules of the PTFE bond or otherwise adhere to each other(as indicated by the cross-hatching of FIG. 3C) to adhere the coating,and specifically the pigments in the coating, to the surface of the bodyof the PTFE tubing. As further seen in FIG. 3C, the heat is applied tothe coated PTFE tubing such that the molecules near the center of thePTFE tubing and the molecules of the PTFE tubing at or near the lumen ofthe PTFE tubing are each increased to lower temperatures (than thetemperature of the molecules of the PTFE tubing at or near the outersurface of the body of the PTFE tubing) which will minimize and/orprevent the decomposition of the PTFE caused by the PTFE being heatedabove the PTFE decomposition temperature of 500° F. (260° C.). It shouldbe appreciated that the cure temperature utilized and the duration whichthe PTFE tubing is cured is based on the composition of the PTFE tubingand/or one or more pigments of the applied coating.

After the final cure, each secured end of the body of the PTFE tubing isreleased as indicated in block 116 of FIG. 1. In one such embodiment,after the final cure, the PTFE tubing remains in the securing device andforced cooling, ramped or controlled reduction in temperature or roomtemperature cooling is employed to minimize any stress relief or otherfactors that may contribute to the shrinking of the PTFE tubing length.The resulting PTFE tubing, as seen in FIG. 2L, includes one or moremarking used to convey information to the medical professional using thePTFE tubing. It should be appreciated that because PTFE tubing oftenflexes or bends when inserted into a patient, the markings bonded to thesurface of the PTFE tubing disclosed herein are enabled to also flex orbend and remain adhered to the PTFE tubing.

It should be appreciated that as described above, if the indicatedmarkings along the length of the body of the PTFE tubing are inaccurate,the PTFE tubing may be inserted too far into a patient or the PTFEtubing may not be inserted far enough into a patient. It should befurther appreciated that as also described above, when PTFE tubing iscured to temperatures above the recommended maximum use temperature of500° F. (260° C.), the dimensions of the PTFE tubing begin to warp orchange. Accordingly, in this embodiment, to counteract any shrinkingalong the length of the body of the PTFE tubing that might occur whenthe PTFE tubing is further or final cured at a designated temperature,such as 650° F. (343.33° C.) for a designated period of time, the PTFEtubing disclosed herein is secured to limit, inhibit or prevent suchshrinking. That is, as described above, compared to known methods ofmarking PTFE tubing, a higher cure temperature facilities a strongerbond or adhesion of the coating to the surface of the PTFE tubing, butthe higher cure temperature is accompanied by warping of the PTFEtubing. Thus, the present disclosure employs the higher cure temperaturewhile simultaneously or substantially simultaneously accounting forand/or otherwise counteracting this potential warping or shrinking alongthe length of the PTFE tubing.

More specifically, because: (i) the body of the PTFE tubing contractswhen heated to a designated temperature, such as at least 650° F.(343.33° C.) for a designated period of time, (ii) the shielding deviceincludes gaps between the masking members (which are spaced apart atmeasured intervals along the length of the shielding device), and (iii)these gaps correspond with the locations of the intended markings to beplaced at measured intervals along the length of the body of the PTFEtubing, as described above and as seen in the illustrated embodiment ofFIGS. 2A to 2L, to ensure that the markings on the fully cured PTFEtubing correspond with the locations of the intended markings, the PTFEtubing is secured in one or more anti-shrinking devices. That is, one ormore anti-shrinking devices are utilized to secure the body of the PTFEtubing such that after the final cure, the actual markings along thelength of the body of the PTFE tubing still accurately correspond to theintended markings placed at measured intervals along the length of thebody of the PTFE tubing.

In one such embodiment, as seen in FIGS. 2J, 2K, 7A and 8, theanti-shrinking device includes utilizing one or more clamps or holderswhich secure or otherwise hold stationary the ends of the body of thePTFE tubing during the further cure. In another such embodiment, as alsoseen in FIG. 7A, the anti-shrinking device additionally or alternativelyincludes utilizing a support member which is fully inserted into thelumen of the PTFE tubing to secure or otherwise hold the body of thePTFE tubing stationary during the further cure. In another suchembodiment, the anti-shrinking device or fixtures includes utilizing oneor more clamps or holders which each include a support member, such as acylindrical rod, that is partially inserted into the lumen of the PTFEtubing. In this embodiment, the clamps engage the outer surface of thebody of the PTFE tubing and the support member engages the inner surfaceof the body of the body of the PTFE tubing to secure or otherwise holdthe body of the PTFE tubing stationary during the further cure.

It should be appreciated that any suitable anti-shrinking device whichinhibits, limits, reduces or prevents the shrinking of the body of thePTFE tubing during the final cure may be utilized in accordance with thepresent disclosure. In different embodiments, the anti-shrinking deviceincludes one or more liquid anti-shrinking devices, one or more gasanti-shrinking devices, one or more solid anti-shrinking devices, one ormore two-dimensional anti-shrinking devices and/or one or morethree-dimensional anti-shrinking devices. Moreover, in differentembodiments, the support member of the anti-shrinking device includesone or more liquid support members, one or more gas support members, oneor more solid support members, one or more two-dimensional supportmembers and/or one or more three-dimensional support members. Forexample, a portion of the outer surface of the coated PTFE tubing iscured at 900° F. (482.22° C.) while water is passed or flowed underpressure through a tubular support member inserted into the lumen of thePTFE tubing. Such water inside the support member functions to removethe heat from the inside surface of the PTFE tubing (i.e., cool the PTFEtubing) to reduce the shrinkage or deformation of the cured PTFE tubing.

In one example, as seen in FIGS. 2I and 4A, the length of the body ofthe PTFE tubing (indicated as X) remains constant from the pre-coated,pre-cured PTFE tubing of FIG. 4A to the coated, pre-cured PTFE tubing ofFIG. 2I, to the coated, cured PTFE tubing of FIG. 4A. As further seen inFIGS. 2I and 4A, the distance between the first applied marking 212 aand the second applied marking 212 b (indicated as Y) on the coated,pre-cured PTFE tubing of FIG. 2I is the same as the distance between thefirst applied marking 212 a and the second applied marking 212 b (alsoindicated as Y) on the coated, cured PTFE tubing of FIG. 4A. As alsoseen in FIGS. 2I and 4A, the length of the first applied marking 212 a(indicated as Z) on the coated, pre-cured PTFE tubing of FIG. 2I is thesame as the length of the first applied marking 212 a (also indicated asZ) on the coated, cured PTFE tubing of FIG. 4A. Accordingly, byproviding that the markings along the length of the body of the PTFEtubing are accurately placed at designated intervals ensures that whensurgeons or other medical professionals have inserted the PTFE tubinginto a patient, the PTFE tubing is actually inserted to the lengthindicated to the surgeons or other medical professionals. Such accurateplacement of the markings benefits patients by reducing the likelihoodthat a medical professional will rely on inaccurate markings along thelength of the PTFE tubing when inserting the PTFE tubing into thepatient.

In one embodiment, in addition to compensating or accounting for anydimensional changes (i.e., any shrinking or contracting) along thelength of the body of the PTFE tubing, any dimensional changes occurringto the diameter of the body of the PTFE tubing are also compensated oraccounted for. Specifically, it should be appreciated that selectivelyheating the coated portions of the body of the PTFE tubing (withoutheating the uncoated portions of the body of the PTFE tubing) causes thediameter of the body of the PTFE tubing at these cured portions tocontract or shrink. Accordingly, in various embodiments of the presentdisclosure, to prevent the cured and uncured portions of the marked PTFEtubing from having different outer diameters, the amount of subsequentreduction in the diameter at certain portions of the PTFE tubing isaccounted for when determining a thickness or amount of coating to beapplied to certain portions of the PTFE tubing. For example, as seen inFIG. 4B, the body of the uncoated, uncured PTFE tubing of FIG. 5A has aninner diameter (indicated as A) which defines the lumen and the uncoateduncured PTFE tubing of FIG. 5A has an outer diameter (indicated as B).In this example, a designated amount or thickness of the coating isapplied to certain portions of the outer surface of the body of the PTFEtubing (as seen in FIG. 5B). In this example, this designated amount orthickness of the coating is determined such that when the body of thePTFE tubing is cured (as seen in FIG. 5C), the amount of applied coatingcompensates for the reduction in the outer diameter of the body of thePTFE tubing. As seen in FIGS. 4B and 5D, this configuration providesthat while the inner diameter of the cured, coated portions of the bodyof the PTFE tubing (indicated as C) will be less than or smaller thanthe inner diameter of the uncured, uncoated portions of the body of thePTFE tubing (indicated as A), the outer diameter of the cured, coatedportions of the body of the PTFE tubing (indicated as B) will be thesame or substantially the same as the uncured, uncoated portions of thebody of the PTFE tubing (indicated as B). Accordingly, such equal orsubstantially equal outer diameters reduces or prevents grooves orvalleys from being created in the surface of the marked PTFE tubing.That is, by accounting for the subsequent reduction in the diameter ofthe PTFE tubing when determining an amount of coating to apply tocertain portions of the PTFE tubing, less bumps or protrusions havingshoulders with sharp edges (which can scrape or irritate bodily tissues,snag vessels or arteries of the patient, or otherwise cause damageand/or trauma to the patient) are created in marking the PTFE tubingdisclosed herein.

In one such embodiment, the size of the markings and/or the number ofmarks grouped together to form a marking indicating different lengths ofthe marked PTFE tubing. In another such embodiment, small markings canbe created at measured intervals along the length of the PTFE tubing toindicate uniform length markers of the PTFE tubing. In anotherembodiment, markings are created to indicate a specific distance from areference point on the PTFE tubing, such as a distance from the middlepoint, the proximal end and/or the distal end. For instance, one band ofa color can indicate a first distance from the distal end, while twobands of colors in close proximity can indicate a second distance fromthe distal end. Likewise, in another embodiment, depending on the sizeand shape of the PTFE tubing, numbers or characters are created on thesurface of the PTFE tubing to indicate a distance from a middle point,the distal end and/or the proximal end. In another embodiment, one ormore geometric shapes, including but not limited to: circles, squares,rectangles, triangles, parallelograms, and other polygrams are createdto indicate lengths of the PTFE tubing.

In another embodiment, a plurality of different colored coatings areapplied to the PTFE tubing such that different colors are created toindicate distances from the middle point, proximal end or distal end ofthe PTFE tubing. In another embodiment, a plurality of different coloredcoatings are applied to the PTFE tubing such that a progression of aplurality of interrupted colors is created along the length of the PTFEtubing. In another embodiment, a plurality of different colored coatingsare applied such that the PTFE tubing includes a first color (which runsfrom a distal end of the PTFE tubing to a halfway or middle point of thePTFE tubing) and a second, different, contrasting color (which runs fromthe proximal end of the PTFE tubing to the halfway or middle point ofthe PTFE tubing). Such a configuration accomplishes that a surgeon ormedical professional can quickly identify when more than 50% of the PTFEtubing is internal to the patient and determine whether a different PTFEtube of a different length should be employed. That is, the PTFE tubingof this embodiment (and other disclosed embodiments wherein differentsegments of a PTFE tubing are marked with different colors) is utilizedby a surgeon or medical professional during a medical procedure todetermine the length of the PTFE tubing inserted into a patient's body(i.e., by observing the color of the segments of the PTFE that areexternal to the patient's body).

It should be appreciated that the markings disclosed herein are notlimited to: indicating lengths, but also can indicate the size, type,material, part number, serial number, lot number, manufacturing date,manufacturer of the PTFE tubing. The markings can also includedirectional arrows, location arrows, bar codes or other codes, or otherproperties or instructions associated with the PTFE tubing. In anotherembodiment, the markings disclosed herein form a band or stripe alongthe entire length or along selected lengths from the distal end to theproximal end of the PTFE tubing. The markings can include a stripeapplied to the outer diameter either in a longitudinal manner or aspiral manner around and along a specified or the entire length of thediameter of the PTFE tubing. In different embodiments, these markingscan form one or more: linear lines, bands or stripes along thelongitudinal axis of the PTFE tubing, spiral patterned lines, bands orstripes along the length of the PTFE tubing, parallel lines, bands orstripes, perpendicular lines, bands or stripes, transverse lines, bandsor stripes, any indicia or marking disclosed herein or any combinationthereof. It should be appreciated that such formed markings can beutilized in combination with any suitable marking disclosed herein todenote one or more dimensions or sizes along the length of the PTFEtubing.

Unsecured Curing Embodiment

In another embodiment, rather than securing the ends of the body of thePTFE tubing prior to the further or final cure, the masking members ofthe shielding device are spaced apart to compensate for the contractionor shrinkage of the length of the cured body of the PTFE tubing. In thisembodiment, to account for the reduction in length of the body of thePTFE tubing caused by the curing process, the masking members of theshielding device are spaced a greater distance apart such that after thefurther or final cure (and the shrinkage of the length of the body ofthe PTFE tubing), the length of the body of the PTFE tubing and themarkings along the length of the body of the PTFE tubing correspondswith the intended length of the body of the PTFE tubing and the intendedmarkings along the length of the body of the PTFE tubing. In one exampleembodiment, if a plurality of masking members of a first shieldingdevice (to be used with PTFE tubing having its ends secured for thefinal cure) are each a first distance apart and the final cure of thebody of the PTFE tubing causes a reduction of the length of the body ofthe PTFE tubing by designated percentage, then the plurality of maskingmembers of a second shielding device (to be used with body of the PTFEtubing having its ends unsecured or free for the final cure) are each asecond distance apart which accounts for this reduction of the length ofthe body of the PTFE tubing by the designated percentage. In thisembodiment, as seen in FIG. 6A, after the coating is selectively appliedto the outer surface of the body of the PTFE tubing and the body of thePTFE tubing is partially cured, the partially cured body of the PTFEtubing has: (i) a first length (indicated as X′), (ii) at least twomarkings which are a first distance apart (indicated as Y′), and (iii)the length of a first of the markings is a first distance (indicated asZ′). As seen in FIG. 6B, the body of the PTFE tubing is positioned in asuitable curing device and cured while both ends of the body of the PTFEtubing remain free or unsecured. Such curing the body of the PTFE tubinghaving free ends causes at least the length of the body of the PTFEtubing to shrink or contract. Accordingly, after the body of the PTFEtubing is cured (with both ends unsecured or free), as seen in FIG. 6C,the length of the body of the PTFE tubing is reduced by the designatedpercentage and the resulting PTFE tubing has: (i) a second length(indicated as X), (ii) at least two markings which are a second distanceapart (indicated as Y), and (iii) the length of a first of the markingsis a second distance (indicated as Z). It should be appreciated thatwhen compared to the PTFE tubing of FIG. 4A (i.e., the PTFE tubing thatis cured with the ends of the PTFE tubing secured), the spacing of themasking members of the shielding device of this embodiment accounts forthe reduction in the length of the PTFE tubing to accomplish that boththe marked PTFE tubing of FIG. 4A and the marked PTFE tubing of FIG. 6Chave: (i) the same length (indicated as X), (ii) at least two markingswhich are the same distance apart (indicated as Y), and (iii) the lengthof a first of the markings is the same distance (indicated as Z). Inthis embodiment, by providing that the markings along the length of thebody of the PTFE tubing are accurately placed at designated intervalsensures that when surgeons or other medical professionals have insertedthe marked PTFE tubing into a patient, the marked PTFE tubing isactually inserted to the length indicated to the surgeons or othermedical professionals.

Alternative for Preparing PTFE Tubing to Coat

In one alternative embodiment, prior to selectively coating the body ofthe PTFE tubing, the body of the PTFE tubing is cleaned by condensing avaporized cleaner on the surface of the body of the PTFE tubing, whereinthe cleaner dissolves and washes away the oils on the surface of thebody of the PTFE tubing. In another embodiment, laser energy from alaser device, such as a YAG laser or CO₂ laser, is directed at thesurface of the PTFE tubing to clean or otherwise selectively etch thesurface of the body of the PTFE tubing.

In another embodiment, the body of the PTFE tubing is cleaned with anultrasonic cleaner used in combination, prior or after the ultrasonicdegreaser, with a solvent such as acetone, alcohol or another degreaser.Alternatively, the body of the PTFE tubing is pre-cleaned or the methodis performed in a “clean room” where the cleaned part is manufacturedand the step is not necessary. In another embodiment, the body of thePTFE tubing is heated to a temperature in excess of at least 450° F.(232.22° C.) for a period of time sufficient to thermally degradesurface impurities, draw oils and other impurities out of any pores inthe surface of the body of the PTFE tubing and create a non-acidic“passivation” of the surface of the body of the PTFE tubing. In anotherembodiment, the body of the PTFE tubing is cleaned in a batch or bulkcleaning method, thereby cleaning all of the surfaces of the body of thePTFE tubing. In another embodiment, the body of the PTFE tubing isheated before applying a coating to reduce ambient moisture on thesurface of the PTFE tubing and improve adhesion of a coating to the bodyof the PTFE tubing. In other embodiments, any combination of thecleaning methods mentioned above are used to improve the cleaningprocess of the body of the PTFE tubing.

Alternative Coatings of PTFE Tubing

In one alternative embodiment, a coating which is formulated withmagnetic receptive pigments and/or electromagnetic receptive pigments isutilized, wherein these magnetic receptive pigments will provideinternal heat when subjected to one or more appropriate magnetic fieldsor electromagnetic fields. In this embodiment, such magnetic receptivepigments are applied to non-magnetic substrates, such as the body of thePTFE tubing. Such magnetic receptive pigments are formulated withlow-friction materials and appropriate color pigments and binders, suchas epoxy and polyimide, which when cured at a suitable temperatureprovides adhesion to the surface of the body of the PTFE tubing. In thisembodiment, the body of the PTFE tubing is subsequently internallyheated by exciting or energizing the dispersed magnetic receptiveparticles.

In one embodiment, a plurality of anti-microbial particles such assilver, ceramic, silver ceramic, silver oxide, glass silver or silvercompounds or any suitable anti-microbial agent are applied to one ormore of the surfaces of the body of the PTFE tubing to reduce and killbacteria and other potential germs that are located on the surface(s) ofthe body of the PTFE tubing or otherwise incorporated into the coatingformulation. In one embodiment, the anti-microbial particles areinterspersed with the uncured coating. During the below-described curingprocess, some of the anti-microbial particles migrate or rise to thesurface of the coating. The anti-microbial particles are capable ofkilling bacteria and other harmful organisms which contact the surfaceof the coated PTFE tubing while in storage or while the medical deviceis deployed into the body. The coated PTFE tubing therefore minimizes orreduces the chance of infections or other complications in the bodyafter the surgical procedure is complete.

In another embodiment, the coating also includes particles of alow-friction material, such as a fluoropolymer material including PTFE,FEP and MFA. In one embodiment, the particles are micron- and/orsub-micron-sized. In another embodiment, the low-friction material isresistant to chemicals such that the low-friction material will providea low surface energy outer layer and will resist corrosion, resistoxidization, resist breaking down, resist forming bonds with othermaterials, and otherwise be unaffected by contacting other chemicals. Inanother embodiment, the low-friction material is pure and free ofcontaminants such that the low-friction material can safely be used inmedical procedures and can safely contact food for human consumption. Inanother embodiment, the low-friction material is irradiated, prior toincorporation in the coating, with an electron beam (or other suitableenergy source) so that the resulting particles create an easily wettedsurface which enables better adhesion to the binder material.

In another embodiment, the coating includes additives, such as silanecoupling agents, acids and other materials formulated to improve thebonding capabilities of a coating to the surface of the body of the PTFEtubing or other materials which modify the curing characteristics or thedrying characteristics of the coating before curing. In anotherembodiment, the coating includes additives to improve the wearcharacteristics, corrosion resistance, and/or electrical properties ofthe coating. In another embodiment, an alcohol (or other suitablesolvent) and a silane coupling agent (or other suitable adhesionpromoting agent) are utilized as a primer dip on the smooth orsemi-smooth surface of the body of the PTFE tubing.

In another embodiment, a radiopaque material, such as barium sulfide,barium sulfate or a suitable metal, such as tungsten or palladium, isincluded in the coating and otherwise applied (or selectively applied)to one or more of the inner or outer surfaces of the body of the PTFEtubing. In this embodiment, the radiopaque material provides that asuitable marking shows up when using a suitable imaging device. In theseembodiments, the surgeon or other medical professional utilize theimaging device to determine an exact location of the PTFE tubing insidea patient and/or to determine one or more measurements inside thepatient.

Alternative Methods of Applying Coating to PTFE Tubing

In one alternative embodiment, the shielding device is made of laserengraved plastic sheet. In another embodiment, the shielding device ismade of a laser engraved adhesive sheet of biaxially-orientedpolyethylene terephthalate (BoPet). In this embodiment, the adhesivesheet is wrapped around selective portions of the body of the uncoated,uncured PTFE tubing and the coating is applied to the unwrapped portionsof the body of the PTFE tubing. In this embodiment, a first cure at 300°F. (148.89° C.) occurs, the adhesive mask is then removed and a finalcure at 650° F. (343.33° C.) occurs. It should be appreciated that anysuitable laser engraved or machined stencil type shield or mask made ofany suitable material, such as stainless steel, copper or aluminum maybe employed as a suitable shielding device.

In different alternative embodiments, the coating is sprayed on, appliedusing an air atomizer or appropriate atomizing device, applied by asiphon, gravity, ultrasonic or pressure pot method which forces thecoating through a nozzle at high pressure such that the coating forms avapor or mist which is directed toward the surface of the body of thePTFE tubing. In these embodiments, the air velocity around the PTFEtubing helps contain any overspray of the coating. In anotherembodiment, the coating is applied with a variation of siphon or gravityspraying wherein the coating is sprayed at a lower pressure and inhigher volume to reduce the amount of volatile organic compoundsreleased during the spraying process. In another embodiment, high speedor low speed rollers are used to apply a film of coating to the surfaceof the body of the PTFE tubing. In another embodiment, the body of thePTFE tubing is passed under a falling curtain of the coating to coat thesurface of the PTFE tubing such that the exposed surface receives acoating on approximately half the outer diameter of the PTFE tubing. Inanother embodiment, a powder coating system is employed. This powdercoating system includes a primer, where required, of a liquid that ispreapplied and either cured to dry or remains wet prior to theapplication of a topcoat of a powder. In another embodiment, anelectrostatic, tribo-charged or opposite electrostatic charged spray orpowder spray method is used to apply the coating to the surface of thebody of the PTFE tubing. The electrostatically charged spray enables anoperator to better control the application uniformity of the coating andthereby enhances the uniformity, density and application of the coatingon the surface of the body of the PTFE tubing. It should be appreciatedthat the coating may have one or more characteristics altered to allowfor more efficient electrostatic, tribo-charged or oppositeelectrostatic charged spray techniques to be used to apply the coatingto a surface of the body of the PTFE tubing.

In another embodiment, the coating is applied vertically orsubstantially vertically while the PTFE tubing is also positionedvertically or substantially vertically. In another embodiment, thecoating is applied horizontally or substantially horizontally while thePTFE tubing is also positioned horizontally or substantiallyhorizontally. In another embodiment, the coating is applied verticallyor substantially vertically while the PTFE tubing is also positionedhorizontally or substantially horizontally. In another embodiment, thecoating is applied horizontally or substantially horizontally while thePTFE tubing is also positioned vertically or substantially vertically.In these embodiments, the curing of the applied coating occurs while thePTFE tubing is positioned vertically or substantially vertically and/orhorizontally or substantially horizontally.

In another embodiment, pad printing is employed to coat one or moreportions of the body of the PTFE tubing. Pad printing utilizes anindirect offset printing process that involves an image beingtransferred from the printing plate via a silicone pad onto the surfaceof the body of the PTFE tubing. It should be appreciated that anysuitable method of applying the coating to one or more portions of anysurface of the body of the PTFE tubing may be employed in accordancewith the present disclosure.

In another embodiment, rather than applying the coating to theunshielded portion(s) of the body of the PTFE tubing in a plurality ofsequential coating applications as described above, a coating is appliedto one or more of the unshielded portions of the body of the PTFE tubingin a single coating application. In this embodiment, to account for thecylindrical shape of the body of the PTFE tubing, the PTFE tubing isrotated as the coating is applied.

In one such embodiment, to facilitate the rotation of the PTFE tubing, asupport member is inserted into the lumen of the PTFE tubing and thesupport member is secured or attached to the PTFE tubing, such as usingone or more fasteners. In one embodiment, the outer diameter of the bodyof the support member is slightly smaller than the inner diameter of thebody of the PTFE tubing such that the support member tightly fits intothe lumen of the PTFE tubing. In another embodiment, the support memberincludes a hollow tube with an outer diameter which is slightly smallerthan the inner diameter of the body of the PTFE tubing. In thisembodiment, when air pressure and/or heat is/are applied to the hollowtube, the hollow tube swells to contact the inner surface of the body ofthe PTFE tubing and support the PTFE tubing. In this embodiment, whenthe hollow tube is subsequently cooled, the hollow tube will shrinkseveral thousandths of an inch in diameter to allow the support tubingto be easily withdrawn. In these embodiments, either before or afterplacing the support member into the lumen of the PTFE tubing, the PTFEtubing is placed in, attached to or otherwise coupled with a suitableshielding device. For example, as seen in FIG. 9C, a support member 328,such as a cylindrical rod, is interested into the lumen 208 of the PTFEtubing 200 and the PTFE tubing (including the support member) is thenplaced in, attached to or otherwise coupled with a suitable shieldingdevice. In one embodiment, when the PTFE tubing (including the supportmember) is placed in, attached to or otherwise coupled with theshielding device, the surface of the PTFE tubing does not contact thesurface of the shielding device (to facilitate the rotation of the PTFEtubing as described below).

As seen in FIGS. 10A and 10B, after placing the PTFE tubing in thedefined channel of the body of the shielding device, the support memberis connected to a rotating device, such as mandrel, which causes thesupport member to rotate in either a clockwise or a counterclockwisedirection. In this example, as the PTFE tubing is secured to the supportmember, the PTFE tubing is thus rotated in either a clockwise or acounterclockwise direction.

As seen in FIG. 10C, while the support member (and the attached PTFEtubing) is rotating, a first coating 210 is applied to a firstunshielded portion of the body of the PTFE tubing from a suitabledirection. As seen in FIG. 10D, after applying the first coating to thefirst unshielded portion of the body of the PTFE tubing, while thesupport member (and the attached PTFE tubing) remains rotating, thefirst coating 210 is then applied to a second unshielded portion of thebody of the PTFE tubing from the suitable direction. In this illustratedembodiment, because of the shape of the body of the PTFE tubing, to bodyof the PTFE tubing is continuously rotated to completely coat theunmasked portions of the body of the PTFE tubing. Such a process ensuresthat the coating is applied to the unblocked, unprotected, unshielded orotherwise unmasked portions of the body of the PTFE tubing.

Alternative Curing Methods for Coating of PTFE Tubing

In one or more of the embodiments described herein, the coated portionsof the body of the PTFE tubing are exposed to temperatures equal to orhigher than the temperatures that will deform the PTFE tubing (i.e.,500° F. (260° C.)) and the uncoated portions of the body of the PTFEtubing are not subjected to such high temperatures. In one embodiment, aheat shielding device, such as a slotted metal mask, is employed toshield the heat from the uncoated portions of the body of the PTFEtubing. In another embodiment, one or more cooling methods are employedto prevent the uncoated portions of the body of the PTFE tubing fromreaching such high temperatures. In one such embodiment, the PTFE tubingis frozen after the coating has been selectively applied. In thisembodiment, while the PTFE tubing is cold or frozen (and specificallywhile the PTFE tubing made from expanded PTFE is cold or frozen), afurther or final cure utilizing hot air or infrared heat is used to curethe coating applied to certain portions of the body of the PTFE tubing.In another such embodiment, one or more metal heat sinks and/or air flowdevices are employed to prevent the uncoated portions of the body of thePTFE tubing (and specifically the PTFE tubing made from expanded PTFE)from reaching such high temperatures. In another embodiment, nitrogen,expanding air and/or inert gasses are passed through the lumen of thePTFE tubing (and specifically the PTFE tubing made from expanded PTFE)to keep the inside of the PTFE tubing cooler. In another embodiment, oneor more spot coolers, such as the Adjustable Spot Cooler—Frigid-X™device manufactured by Nex Flow™ Air Products Corp are employed toremove heat or btu's from the lumen(s) of the PTFE tubing (andspecifically the PTFE tubing made from expanded PTFE). It should beappreciated that any suitable manner of preventing one or more portionsof the body of the PTFE tubing from being heated (to the decompositiontemperature of such PTFE tubing) may be employed in accordance with thepresent disclosure.

In different embodiments, radiated heat is applied from a radiantsource, such as hot air, open flame, heated filaments, or lasers. In oneembodiment, hot air is blown toward a specific coated portion of thebody of the PTFE tubing through a nozzle or other apparatus of directingor funneling air. In another embodiment, heat is directly applied to thesurface of the coated portion of the body of the PTFE tubing coatingsuch that intimate contact occurs between the heat source and the coatedsurface.

In another illustrated embodiment, as seen in FIGS. 7A and 7 b, amagnetic member 404, such as a cylindrical rod formed from amagnetic-type stainless or otherwise appropriate steel, is interestedinto the lumen 208 of the PTFE tubing 200. In one such embodiment, thediameter of the magnetic member is less than the inner diameter of thebody of the PTFE tubing such that, as described above, the innerdiameter of the body of the PTFE tubing is enabled to contract duringthe curing process. In this embodiment, one or more induction coils 406are then placed around the body of the PTFE tubing. The induction coilsare placed along the length of the body of the PTFE tubing to correspondto the coated portions of the body of the PTFE tubing. The coatedportions of the body of the PTFE tubing are then heated by magneticinduction wherein the induction coils are energized with a frequencycurrent, which imparts thermal energy. Specifically, electricalresistance in the magnetic member causes electrical current energy totransform into heat energy. Heat from the magnetic member then transfersto the coating by thermal conduction, thus causing the coating to cure.This method also has the advantage of keeping the body of the PTFEtubing at a cooler temperature.

In another embodiment, infrared heat is directed to a portion of thecoating. In one such embodiment, a first infrared bulb is placed above acoated portion of the body of the PTFE tubing and a second infrared bulbis placed below the coated portion of the body of the PTFE tubing. Inthis embodiment, the infrared heat is selectively applied to the coatedportion of the body of the PTFE tubing. In another such embodiment, twoinfrared bulbs are placed relative to the coated portion of the body ofthe PTFE tubing and a heat shielding device, such as a slotted metalmask, is employed to shield the heat from the uncoated portions of thebody of the PTFE tubing. In these embodiments, the at least partiallytransparent body of the PTFE tubing enables certain designated amountsof infrared heat to pass through the body of the PTFE tubing to thecoating, which absorbs the heat. This method heats the coating whilesimultaneously keeping the uncoated portions of the body of the PTFEtubing at a cooler temperature.

In another embodiment, the anti-shrinking device includes two clampswhich, along with the coated, partially cured PTFE tubing, are placed ina curing device, such as an oven, and the coated PTFE tubing is cured at650° F. (343.33° C.) for fifteen minutes. In another embodiment, as seenin FIG. 8, one of the clamps and part of the coated, partially curedPTFE tubing are placed in a curing device, such as an oven 410, and oneof the claims and part of the coated, partially cured PTFE tubing is notplaced in the curing device. In this embodiment, the coated PTFE tubingwhich is placed in the curing device is cured at 650° F. (343.33° C.)for fifteen minutes to cause the coating to bond to the surface of thePTFE tubing. It should be appreciated that because these embodimentsinclude curing both the coated portions and the uncoated portions of thePTFE tubing, the diameter of both the coated portions and the uncoatedportions of the PTFE tubing are reduced.

It should be appreciated that because the holder or clamps of theanti-shrinking device may or may not be heated along with the partiallycured PTFE tubing and because a portion of the PTFE tubing disclosedherein may be discarded, any suitable type of holder made of anysuitable material may be used in accordance with the present disclosure.In one such embodiment, as seen in FIG. 8, a first type of holder 402 c,such as a metal holder suitable to be placed in a curing device, such asan oven, is used to secure a first end of the body of the coated PTFEtubing and a second type of holder 402 d not suitable to be placed in acuring device, such as a silicone rubber or rubber molded clamp, is usedto secure a second end of the body of the coated PTFE tubing. In oneembodiment, the holders or clamps of at least one of the ends of thepartially cured PTFE tubing directly engage the surface of the PTFEtubing. In this embodiment, the clamp engages a designated length, suchas two inches, of the outer surface of the body of the PTFE tubing tohold the body of the PTFE tubing secure and limit or prevent the body ofthe PTFE tubing from shrinking. In another embodiment, one or more ofthe clamps is configured with a support member which is partiallyinserted into the lumen of the PTFE tubing. In this embodiment, thesupport member engages the inner surface of the body of the PTFE tubingand the clamp engages a designated length of the outer surface of thebody of the PTFE tubing to hold the body of the PTFE tubing secure andlimit or prevent the body of the PTFE tubing from shrinking.

As described above, because the force applied by the clamps or holdersof the anti-shrinking device may damage the PTFE tubing, certain of theclamps are often employed when one piece of PTFE tubing is coated andthen cut into a plurality of smaller pieces of PTFE tubing (with thedamaged ends cut and discarded). In another embodiment, rather than theholders or clamps directly engaging the body of the PTFE tubing, aprotector, such as a pad, is placed between at least one of the holdersand the body of the PTFE tubing. Such protectors prevent the holders orclamps from directly engaging the body of the PTFE tubing and protectthe PTFE tubing from any damage potentially caused by the clamping ofthe PTFE tubing.

In another embodiment, monel or inconel rings (which are resistanceheated) emit convection heat to cure the coated portions of the body ofthe PTFE tubing. In one such embodiment, electrical current is passedthru horse shoe shaped inconel rings to raise the temperature of theinconel ring to 2000° F. (1093.33° C.). The inconel ring then emits bothconvection heat and infrared energy to cure the coating selectivelyapplied to a portion of the outer surface of the body of the PTFEtubing.

In another embodiment, microwave heat is used to cure the coatedportions of the body of the PTFE tubing. In another embodiment, one ormore of the heat or energy sources described herein is coupled with theflow of water, oil or any suitable heat dispersing fluid thru the PTFEtubing (or thru a fluid containing device inserted into the lumen of thePTFE tubing) to facilitate the selective curing of certain coatedportions of the body of the PTFE tubing. In another embodiment, heatingelements having an outer diameter smaller than the lumen of the PTFEtubing are inserted into the lumen of the PTFE tubing and cure theapplied coating. In one such embodiment, one or more heated tubes whichuse compressed air passing thru a heated tube are placed relative to thecoated portions of the body of the PTFE tubing and are utilized toselectively heat such coated portions of the body of the PTFE tubing.

It should be appreciated that any suitable external energy source, suchas flame heat, short and medium wave infrared, hot air (electricallyheated) with accurately placed orifices to make a specific and accuratemarks on the PTFE tubing, induction heat provided through a “bobby pin”or circular shaped coil and/or at right angles, heat provided usinginduction energy, and/or any combination of the curing methods disclosedherein may be used to cure the applied coating.

In another embodiment, one or more anti-shrinking devices, (such as oneor more cylindrical metal rod support members or one or more tubingsupport members which may/may not be heated and/or cooled with liquidsand/or gasses) are inserted into one or more defined lumens of the PTFEtubing. In this embodiment, when on or more portions of the body of thePTFE tubing are selectively cured, a portion of the heat or energy fromthe selective cure is transferred from the PTFE tubing to the supportmember. Such heat or energy transfer at least partially dissipates theheat or energy and reduces the temperature which the surface of the PTFEtubing rises to (or at least which the uncured surface of the PTFEtubing rises to) and thus reduces the decomposition, warp and shrinkageof the PTFE tubing (both along the circumference of the PTFE tubing andalong the length of the PTFE tubing). Accordingly, such anti-shrinkingdevices serves a plurality of different functions including supportingthe PTFE tubing during coating and curing, facilitating in the rotationof the PTFE tubing during coating and curing, absorbing and dissipatingheat applied to the PTFE tubing during curing.

In another embodiment, one or more anti-shrinking devices are insertedinto one or more defined lumens of the PTFE tubing and the PTFE tubingis then rotated to further increase the distribution of the heat orenergy transferred to the PTFE tubing. In one such embodiment, as seenin FIG. 11A, to facilitate the rotation of the PTFE tubing, ananti-shrinking device, such as support member 328 is inserted into thelumen of the PTFE tubing and the anti-shrinking device is connected to arotating device which causes the anti-shrinking device (and the PTFEtubing) to rotate in either a clockwise or a counterclockwise direction.In this example, as seen in FIG. 11C, following the application of thecoating 210 to a first unshielded portion of the body of the PTFEtubing, the coated portion of the body of the PTFE tubing is selectivelyheated (without heating the uncoated portions of the body of the PTFEtubing). As seen in FIG. 11D, such selective heating coupled with therotation of the PTFE tubing causes the diameter of the body of the PTFEtubing at these cured portions to contract or shrink. Accordingly, invarious embodiments of the present disclosure, to prevent the cured anduncured portions of the marked PTFE tubing from having different outerdiameters, the amount of subsequent reduction in the diameter at certainportions of the PTFE tubing is accounted for when determining athickness or amount of coating to be applied to certain portions of thePTFE tubing.

In another embodiment, a supporting member is configured to utilize thecontraction or shrinkage of the cured portions of the PTFE tubing. Inone such embodiment, the supporting member is configured such that thecure of the PTFE tubing selectively reduces the size or diameter of thePTFE tubing to create a PTFE tubing with optimum dimensions and markingspermanently bonded in the appropriate areas. For example, if a supportmember with tapered end(s) is inserted into the lumen of the PTFEtubing, then after the further cure, the end(s) of the PTFE tubing willcontract or shrink to create tapered end(s). In this example, suchcreated tapered end(s) provide for easier insertion into a patient.

In another embodiment, one side of the surface of the PTFE tubing iscured while the opposite side of the surface of the PTFE tubing iscooled to further control the shrinking or compacting of the PTFEtubing.

Additional Markings/Coatings on PTFE Tubing

In another embodiment, in addition to the markings formed along thesurface of the body of the PTFE tubing by selectively applying one ormore coatings, one or more additional markings are created in either theapplied coating or the surface of an uncoated portion of the body of thePTFE tubing. For example, laser energy, from a CO₂ laser, a fiber laseror a YAG laser, is utilized to ablate a distinctive mark or markingsinto either the coating applied to the surface of the PTFE tubing or thesurface of an uncoated portion of the body of the PTFE tubing. Forexample, a coating of a first color, such as black, is applied to aportion of the body of the PTFE tubing and then a CO₂ laser is utilizedto laser engrave a contrasting marking, such as a work number or a partnumber, in the coated and cured portion of the body of the PTFE tubing.

Such additional markings indicate one or more of: a length, a size ofthe PTFE tubing, a type of the PTFE tubing, a material, a part number ofthe PTFE tubing, a serial number of the PTFE tubing, a lot number of thePTFE tubing, a manufacturing date of the PTFE tubing, a manufacturer ofthe PTFE tubing, a bar code or other code, a property or instructionassociated with the PTFE tubing, an arrow, a band or a stripe along theentire length or along selected lengths from the distal end to theproximal end of the PTFE tubing, a linear line, a band or stripe alongthe longitudinal axis of the PTFE tubing, spiral patterned lines, bandsor stripes along the length of the PTFE tubing, parallel lines, bands orstripes, perpendicular lines, bands or stripes, transverse lines, bandsor stripes, any indicia or marking disclosed herein or any combinationthereof.

In another embodiment, a clear or transparent top coat is applied to oneor more of the surfaces of the body of the coated PTFE tubing after thecoating has been selectively applied to the exposed surfaces of the bodyof the PTFE tubing. In one embodiment, the top coating is a low-frictionor release coating or material, such as fluorinated materials,polytetrafluoroethylene, microfine FEP, melt processable pigmentedpowders made into liquid coatings, a low-melt low-molecular weight PTFEresin with the appropriate pigments, perfluoro-alkoxy,fluoroethylenepropylene, MFA, microfine MFA, polyethylene, silicone, aresin like clear medical grade epoxy in liquid or power form, ceramiccomposites, paralyene silane polymers and other suitable low-frictioncoatings. Such a top coating provides that the markings described aboveare substantially covered or sealed underneath an additional layer skinof a low-friction coating.

Further Alternative Embodiments

In another embodiment, to account for the reduction in diameter of thebody of the PTFE tubing caused by the curing process, prior to the finalcure of the body of the coated PTFE tubing, a support and anti-shrinkingdevice, such as a cylindrical metal rod or a hollow tube (which may/maynot be heated and/or cooled with liquids and/or gasses), is insertedinto the defined lumen of the PTFE tubing. In another embodiment whereinthe PTFE tubing defines a plurality of lumens, the support device isconfigured to be inserted into one or more of the plurality of lumensdefined by the PTFE tubing. In these embodiments, the support deviceprevents or inhibits the inner diameter of the body of the PTFE tubingfrom contracting or substantially contracting when the PTFE tubing isheated. In one such embodiment, the support device further prevents thePTFE tubing from being crushed or damaged when the ends of the PTFEtubing are placed in suitable clamps. In this embodiment, the supportdevice enables the clamp to exert additional force on the PTFE tubingwithout otherwise damaging the PTFE tubing.

In another embodiment, the low-friction medical device is made from anon-fluoropolymer substrate, such as metal substrate. In thisembodiment, a first fluoropolymer coating including at least one pigment(or a combination of different pigments) is applied to thenon-fluoropolymer substrate. After applying the first fluoropolymercoating, a second fluoropolymer coating including at least one differentpigment (or a different combination of different pigments) is applied tothe first fluoropolymer coating. In one such embodiment, this secondfluoropolymer coating is selectively applied to the first fluoropolymercoating, such as utilizing any of the above-described shielding devices.

In this embodiment, following the application of the secondfluoropolymer coating, the low-friction medical device of thisembodiment is then cured to a designated temperature (such as above 500°F. (260° C.) at which the fluoropolymer coatings begin to decompose) tocause the first fluoropolymer coating to bond with the secondfluoropolymer coating. As described above with respect to the curing ofthe coating to the low-friction medical tubing, such a cure causes themolecules at or near the surface of the applied first fluoropolymercoating and the molecules at or near the surface of the applied secondfluoropolymer coating to melt. The melted coatings bond or otherwiseadhere to each other to adhere the first fluoropolymer coating and thesecond fluoropolymer coating together. Such an embodiment thus providesa method to securely adhere one or more markings to one or morefluoropolymer coated non-fluoropolymer substrates, such as one or morePTFE coated non-fluoropolymer substrates. This embodiment thusfacilitates that one or more coatings of a first color are permanentlybonded to a fluoropolymer coating of a second color, such as a Teflon°coating (manufactured by DuPont™) to create one or more markings asdisclosed herein.

It should be appreciated that in one such embodiment, thenon-fluoropolymer substrate does not deform as a result of this cure andthus the non-fluoropolymer substrate of this embodiment does not need tobe held or stabilized as described above with respect to the use of ananti-shrinking device with low-friction medical tubing. In another suchembodiment, the non-fluoropolymer substrate deforms as a result of thiscure and thus the non-fluoropolymer substrate of this embodiment needsto be held or stabilized as described above with respect to the use ofan anti-shrinking device with low-friction medical tubing.

It should be appreciated that any of the methods of manufacturing PTFEtubing disclosed herein may be fully or partially manually performed. Itshould also be appreciated that any of the methods of manufacturing PTFEtubing disclosed herein may be fully or partially automated forprecision. It should further be appreciated that any of the methods ofmanufacturing PTFE tubing disclosed herein may be individually performedon a single PTFE tube or simultaneously performed for a plurality ofPTFE tubes.

For the purposes of this application only, the low-friction medicaldevice is referred to and illustrated as medical tubing or PTFE tubing.However, the low-friction medical device disclosed herein can also beany low-friction device that is inserted into a patient or connects to alow-friction device that inserts a device into a patient in connectionwith any medical procedure. Such suitable low-friction medical devicesinclude, but are not limited to: medical tubes, intravenous therapy (IV)tubes, valves, ports, medical wires, medical tapes, medical guide wires,catheters, needles, soft tissue needles, biopsy devices, biopsy tubularsampling devices, soft tissue biopsy devices, soft tissue tubulardevices, hook-type biopsy devices, laminates, vents, medical patches,orthapaedic implants (made from fluoropolymers, such as e-PTFE),fluoropolymer based low-friction implantable surfaces, cannulas, probes,electrosurgical electrodes, sheets, gaskets, blades and knives. Forexample, any suitable low friction, low surface area medical devicewhich flexes, bends or is required to move in any suitable direction maybe marked or coated in accordance with the present disclosure. Indifferent embodiments, the low-friction medical device is constructedfrom any suitable low-friction and/or low surface energy material,including but not limited to one or more of: solid PTFE, non-solid PTFE,expanded PTFE, porous PTFE, micro-porous PTFE, cellular PTFE,fluorinated ethylene propylene (FEP), polyethylene (PE), perfluoroalkoxy(PFA), any suitable fluoropolymer or any low surface energy particulatematerial. Other suitable materials of which a medical device may beconstructed include but are not limited to one or more of: naturalmaterials, synthetic materials, combinations of natural and syntheticmaterials, polyamides, non-metallic composite materials, metals such assteel (both high-carbon and low-carbon content), stainless steel,aluminum, titanium, copper, nickel, bronze, silver, nitinol and othermetals or metal alloys, glass, acrylic, carbon, graphite, cellulose,fabric, ceramics, rubber, any suitable polymer material and any suitableplastic, including but not limited to: nylon, polyetheretherketone(PEEK), polyetherketone (PEK), polyphenylenesulphide (PPS),acrylonitrile-butadiene-styrene (ABS), polycarbonate, epoxy, polyester,and phenolic, or any combination thereof. It should also be appreciatedthat in certain embodiments in which the medical device is a differentdevice than the medical tubing described herein, the shielding deviceand/or the anti-shrinking device utilized as described above is suitableshaped and configured to operate with this different device.

It should further be appreciated that while the above-describedembodiments pertaining to applying a coating, curing the applied coatingto a designated temperature, utilizing one or more anti-shrinkingdevices and exhausting any potentially harmful byproducts are describedand illustrated in relation to medical tubing or PTFE tubing, theseabove-described embodiments may also be utilized with respect to anysuitable low-friction non-medical device. Such suitable low-frictionnon-medical devices include, but are not limited to: sight tubes, airmeters, gas meters, flow meters which include a ball inside a tube,beakers, beaker covers, test tubes, centrifuge tubes, flasks, volumetricflasks, Erlenmeyer flasks, ampules, burettes, condensers, cuvettes,cylinders, dishes, well plates, mortars, pestles, bottles, droppingbottles, bottle pourers, wash bottles, carboys, jars, vials, sleeves,sleeves for glass joints, adapters for glass joints, funnels, Buchnerfunnels, evaporating dishes, petri dishes, crucibles, syringes,micro-titre plates, dippers, ladles, scoopers, bags, stir bars, magneticstir bars, tweezers, forceps, cookware, bakeware, sports strings,musical strings, transparent vessels, translucent vessels, and moldedcontainers. In different embodiments, the non-medical device isconstructed from any suitable low-friction and/or low surface energymaterial, including but not limited to one or more of: solid PTFE,non-solid PTFE, expanded PTFE, porous PTFE, micro-porous PTFE, cellularPTFE, fluorinated ethylene propylene (FEP), polyethylene (PE),perfluoroalkoxy (PFA), any suitable fluoropolymer or any low surfaceenergy particulate material. Other suitable materials of which anon-medical device may be constructed include, but are not limited toone or more of: natural materials, synthetic materials, combinations ofnatural and synthetic materials, polyamides, non-metallic compositematerials, metals such as steel (both high-carbon and low-carboncontent), stainless steel, aluminum, titanium, copper, nickel, bronze,silver, nitinol and other metals or metal alloys, glass, acrylic,carbon, graphite, cellulose, fabric, ceramics, rubber, any suitablepolymer material and any suitable plastic, including but not limited to:nylon, polyetheretherketone (PEEK), polyetherketone (PEK),polyphenylenesulphide (PPS), acrylonitrile-butadiene-styrene (ABS),polycarbonate, epoxy, polyester, and phenolic, or any combinationthereof. It should also be appreciated that in certain embodiments inwhich the non-medical device is a different device than the tubingdescribed herein, the shielding device and/or the anti-shrinking deviceutilized as described above is suitable shaped and configured to operatewith this different device.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. A method of manufacturing acoated polytetrafluoroethylene tube, said method comprising: inserting asupport member into a lumen of a body of a polytetrafluoroethylene tube;coupling the support member and the body of the polytetrafluoroethylenetube to a shielding device; blocking, via the shielding device, aplurality of spaced apart portions of an outer surface of the body ofthe polytetrafluoroethylene tube; rotating the support member and thebody of the polytetrafluoroethylene tube; while rotating the supportmember and the body of the polytetrafluoroethylene tube, applying acoating to each of a plurality of spaced apart unblocked portions of theouter surface of the body of the polytetrafluoroethylene tube; andcuring the applied coating to cause the applied coating to bond to theouter surface of the body of the polytetrafluoroethylene tube toindicate a plurality of spaced apart markings formed on the outersurface of the body of the polytetrafluoroethylene tube.
 2. The methodof claim 1, wherein the support member includes a cylindrical rod. 3.The method of claim 1, wherein the support member includes a hollowtube.
 4. The method of claim 1, wherein the support member has an outerdiameter that is smaller than an inner diameter of the lumen of the bodyof the polytetrafluoroethylene tube.
 5. The method of claim 1, whichincludes securing the body of the polytetrafluoroethylene tube to thesupport member.
 6. The method of claim 1, wherein the support member islonger than the body of the polytetrafluoroethylene tube.
 7. The methodof claim 1, wherein coupling the support member and the body of thepolytetrafluoroethylene tube to the shielding device includes attachingthe support member to a first member of the shielding device.
 8. Themethod of claim 7, wherein blocking, via the shielding device, theplurality of spaced apart portions of the outer surface of the body ofthe polytetrafluoroethylene tube includes attaching a second member tothe first member, the second member including a plurality of blockingportions.
 9. The method of claim 8, wherein the second member defines aplurality of apertures.
 10. The method of claim 8, wherein the secondmember is securable to the first member.
 11. The method of claim 8,wherein the second member defines a plurality of slots.
 12. The methodof claim 8, wherein the second member defines a plurality ofsemi-cylindrical tube engagement surfaces.
 13. The method of claim 7,wherein the first member defines a plurality of semi-cylindrical tubeengagement surfaces.
 14. The method of claim 1, wherein the coatingincludes a polytetrafluoroethylene.
 15. The method of claim 1, whereinthe coating includes a binder selected from the group consisting of: anepoxy, a phenolic, a phenoxy, a polyimide, a polyamide, apolyamide-amide, a polyphenylene sulfide, a polyarylsulfone,polyethylene, a polytetrafluoroethylene, a fluorinated ethylenepropylene, a perfluoroalkoxy, tetrafluoroethylene-hexafluoropropylene, apolyetheretherketone, a polyetherketone, and a tetrafluoroethyleneperfluoromethyl vinyl ether copolymer.
 16. The method of claim 1,wherein the coating includes a pigment selected from the groupconsisting of: an organic pigment, an inorganic pigment, an extenderpigment, a magnetic receptive pigment, and a laser excitable pigment.17. The method of claim 1, wherein the coating includes a pigmentselected from a group consisting of: a phthalocyanine blue, aphthalocyanine green, a diarylide yellow, a diarylide orange, aquanacridone, a naphthol, a toluidine red, a carbizole violet, a carbonblack, an iron oxide red, an iron oxide yellow, a chrome oxide green, atitanium oxide white, a cadmium red, a ultramarine blue, a moly orange,a lead chromate yellow, a mixed metal oxide, a talc, a calciumcarbonate, a silicate and sulfate, a silica, a mica, an aluminum hydrateand silicate, a barium sulfate, a pearl pigment, a kaolin, an aluminumsilicate derivative, an antomony trioxide, a metallic pigment, analuminum flake pigment, and an iron oxide.
 18. The method of claim 1,wherein the coating includes a plurality of anti-microbial particles.19. The method of claim 18, wherein the anti-microbial particles areselected from the group consisting of: silver particles, glass-silverparticles, silver-ceramic particles, and ceramic particles.
 20. Themethod of claim 1, wherein the polytetrafluoroethylene tube is selectedfrom the group consisting of: a cellular polytetrafluoroethylene tube, aporous polytetrafluoroethylene tube, and an expandedpolytetrafluoroethylene tube.
 21. The method of claim 1, whereinapplying the coating to each of the plurality of spaced-apart unblockedportions of the outer surface of the body of the polytetrafluoroethylenetube includes: (i) applying the coating to a first one of the unblockedportions of the outer surface of the body of the polytetrafluoroethylenetube; and (ii) subsequently applying the coating to a second one of theunblocked portions of the outer surface of the body of thepolytetrafluoroethylene tube.
 22. The method of claim 1, whereinapplying the coating to each of the plurality of spaced-apart unblockedportions of the outer surface of the body of the polytetrafluoroethylenetube includes: (i) applying the coating to a first one of the unblockedportions of the outer surface of the body of the polytetrafluoroethylenetube; and (ii) simultaneously applying the coating to a second one ofthe unblocked portions of the outer surface of the body of thepolytetrafluoroethylene tube.
 23. The method of claim 1, wherein curingthe applied coating includes heating the coating to a designatedtemperature for a designated period of time.
 24. The method of claim 23,wherein the designated temperature is at least a decompositiontemperature of the polytetrafluoroethylene tube.
 25. The method of claim1, wherein curing the applied coating includes heating the coating andthe body of the polytetrafluoroethylene tube to a designated temperaturefor a designated period of time.
 26. The method of claim 25, wherein thedesignated temperature is at least a decomposition temperature of thepolytetrafluoroethylene tube.
 27. The method of claim 1, wherein curingthe applied coating includes heating the coating and a plurality ofselective portions of the body of the polytetrafluoroethylene tube towhich the coating is applied to a designated temperature for adesignated period of time.
 28. The method of claim 27, wherein thedesignated temperature is at least a decomposition temperature of thepolytetrafluoroethylene tube.
 29. The method of claim 27, whereinheating the coating and plurality of selective portions of the body ofthe polytetrafluoroethylene tube to which the coating is appliedincludes using an energy source selected from the group consisting of: aradiant heat, induction energy, hot air, open flame, at least oneelectric filament, at least one magnet, and at least one laser.
 30. Themethod of claim 29, wherein the designated temperature is at least adecomposition temperature of the polytetrafluoroethylene tube.
 31. Themethod of claim 1, wherein curing the applied coating includes using anenergy source selected from the group consisting of: a radiant heat,induction energy, hot air, open flame, at least one electric filament,at least one magnet, and at least one laser.
 32. The method of claim 1,wherein the plurality of spaced apart markings are selected from thegroup consisting of: at least one line perpendicular to a longitudinaldirection of the body of the polytetrafluoroethylene tube, at least oneline transverse to the longitudinal direction of the body of thepolytetrafluoroethylene tube, and at least one line substantiallytransverse to the longitudinal direction of the body of thepolytetrafluoroethylene tube.
 33. The method of claim 1, wherein thesupport member functions as an anti-shrinking device when in the lumenof the body of the polytetrafluoroethylene tubing.
 34. The method ofclaim 1, which includes allowing the body of the polytetrafluoroethylenetube to shrink in a longitudinal direction of the body of thepolytetrafluoroethylene tube such that the plurality of spaced-apartmarkings are at desired positions along the body of thepolytetrafluoroethylene tube after such shrinkage.
 35. The method ofclaim 1, wherein coupling the support member and the body of thepolytetrafluoroethylene tube to the shielding device includes attachingthe support member to the shielding device without the outer surface ofthe body of the polytetrafluoroethylene tube contacting the shieldingdevice.
 36. The method of claim 1, which includes applying a top coat tothe cured coating and the body of the polytetrafluoroethylene tube.